1
|
Li X, Ma Y, Liang S, Tian Y, Yin S, Xie S, Xie H. Comparative genomics of 84 Pectobacterium genomes reveals the variations related to a pathogenic lifestyle. BMC Genomics 2018; 19:889. [PMID: 30526490 PMCID: PMC6286560 DOI: 10.1186/s12864-018-5269-6] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2018] [Accepted: 11/19/2018] [Indexed: 11/25/2022] Open
Abstract
BACKGROUND Pectobacterium spp. are necrotrophic bacterial plant pathogens of the family Pectobacteriaceae, responsible for a wide spectrum of diseases of important crops and ornamental plants including soft rot, blackleg, and stem wilt. P. carotovorum is a genetically heterogeneous species consisting of three valid subspecies, P. carotovorum subsp. brasiliense (Pcb), P. carotovorum subsp. carotovorum (Pcc), and P. carotovorum subsp. odoriferum (Pco). RESULTS Thirty-two P. carotovorum strains had their whole genomes sequenced, including the first complete genome of Pco and another circular genome of Pcb, as well as the high-coverage genome sequences for 30 additional strains covering Pcc, Pcb, and Pco. In combination with 52 other publicly available genome sequences, the comparative genomics study of P. carotovorum and other four closely related species P. polaris, P. parmentieri, P. atrosepticum, and Candidatus P. maceratum was conducted focusing on CRISPR-Cas defense systems and pathogenicity determinants. Our analysis identified two CRISPR-Cas types (I-F and I-E) in Pectobacterium, as well as another I-C type in Dickeya that is not found in Pectobacterium. The core pathogenicity factors (e.g., plant cell wall-degrading enzymes) were highly conserved, whereas some factors (e.g., flagellin, siderophores, polysaccharides, protein secretion systems, and regulatory factors) were varied among these species and/or subspecies. Notably, a novel type of T6SS as well as the sorbitol metabolizing srl operon was identified to be specific to Pco in Pectobacterium. CONCLUSIONS This study not only advances the available knowledge about the genetic differentiation of individual subspecies of P. carotovorum, but also delineates the general genetic features of P. carotovorum by comparison with its four closely related species, thereby substantially enriching the extent of information now available for functional genomic investigations about Pectobacterium.
Collapse
Affiliation(s)
- Xiaoying Li
- Beijing Agro-Biotechnology Research Center, Beijing Academy of Agriculture and Forestry Sciences, Beijing, 100097 People’s Republic of China
- Beijing Key Laboratory of Agricultural Genetic Resources and Biotechnology, Beijing, 100097 People’s Republic of China
| | - Yali Ma
- Beijing Agro-Biotechnology Research Center, Beijing Academy of Agriculture and Forestry Sciences, Beijing, 100097 People’s Republic of China
- Beijing Key Laboratory of Agricultural Genetic Resources and Biotechnology, Beijing, 100097 People’s Republic of China
| | - Shuqing Liang
- Health Time Gene Institute, Shenzhen, Guangdong 518000 People’s Republic of China
| | - Yu Tian
- Beijing Agro-Biotechnology Research Center, Beijing Academy of Agriculture and Forestry Sciences, Beijing, 100097 People’s Republic of China
- Beijing Key Laboratory of Agricultural Genetic Resources and Biotechnology, Beijing, 100097 People’s Republic of China
| | - Sanjun Yin
- Health Time Gene Institute, Shenzhen, Guangdong 518000 People’s Republic of China
| | - Sisi Xie
- Health Time Gene Institute, Shenzhen, Guangdong 518000 People’s Republic of China
| | - Hua Xie
- Beijing Agro-Biotechnology Research Center, Beijing Academy of Agriculture and Forestry Sciences, Beijing, 100097 People’s Republic of China
- Beijing Key Laboratory of Agricultural Genetic Resources and Biotechnology, Beijing, 100097 People’s Republic of China
| |
Collapse
|
2
|
Molecular basis of usher pore gating in Escherichia coli pilus biogenesis. Proc Natl Acad Sci U S A 2013; 110:20741-6. [PMID: 24297893 DOI: 10.1073/pnas.1320528110] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Extracellular fibers called chaperone-usher pathway pili are critical virulence factors in a wide range of Gram-negative pathogenic bacteria that facilitate binding and invasion into host tissues and mediate biofilm formation. Chaperone-usher pathway ushers, which catalyze pilus assembly, contain five functional domains: a 24-stranded transmembrane β-barrel translocation domain (TD), a β-sandwich plug domain (PLUG), an N-terminal periplasmic domain, and two C-terminal periplasmic domains (CTD1 and 2). Pore gating occurs by a mechanism whereby the PLUG resides stably within the TD pore when the usher is inactive and then upon activation is translocated into the periplasmic space, where it functions in pilus assembly. Using antibiotic sensitivity and electrophysiology experiments, a single salt bridge was shown to function in maintaining the PLUG in the TD channel of the P pilus usher PapC, and a loop between the 12th and 13th beta strands of the TD (β12-13 loop) was found to facilitate pore opening. Mutation of the β12-13 loop resulted in a closed PapC pore, which was unable to efficiently mediate pilus assembly. Deletion of the PapH terminator/anchor resulted in increased OM permeability, suggesting a role for the proper anchoring of pili in retaining OM integrity. Further, we introduced cysteine residues in the PLUG and N-terminal periplasmic domains that resulted in a FimD usher with a greater propensity to exist in an open conformation, resulting in increased OM permeability but no loss in type 1 pilus assembly. These studies provide insights into the molecular basis of usher pore gating and its roles in pilus biogenesis and OM permeability.
Collapse
|
3
|
The structure of the PapD-PapGII pilin complex reveals an open and flexible P5 pocket. J Bacteriol 2012; 194:6390-7. [PMID: 23002225 DOI: 10.1128/jb.06651-11] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
P pili are hairlike polymeric structures that mediate binding of uropathogenic Escherichia coli to the surface of the kidney via the PapG adhesin at their tips. PapG is composed of two domains: a lectin domain at the tip of the pilus followed by a pilin domain that comprises the initial polymerizing subunit of the 1,000-plus-subunit heteropolymeric pilus fiber. Prior to assembly, periplasmic pilin domains bind to a chaperone, PapD. PapD mediates donor strand complementation, in which a beta strand of PapD temporarily completes the pilin domain's fold, preventing premature, nonproductive interactions with other pilin subunits and facilitating subunit folding. Chaperone-subunit complexes are delivered to the outer membrane usher where donor strand exchange (DSE) replaces PapD's donated beta strand with an amino-terminal extension on the next incoming pilin subunit. This occurs via a zip-in-zip-out mechanism that initiates at a relatively accessible hydrophobic space termed the P5 pocket on the terminally incorporated pilus subunit. Here, we solve the structure of PapD in complex with the pilin domain of isoform II of PapG (PapGIIp). Our data revealed that PapGIIp adopts an immunoglobulin fold with a missing seventh strand, complemented in parallel by the G1 PapD strand, typical of pilin subunits. Comparisons with other chaperone-pilin complexes indicated that the interactive surfaces are highly conserved. Interestingly, the PapGIIp P5 pocket was in an open conformation, which, as molecular dynamics simulations revealed, switches between an open and a closed conformation due to the flexibility of the surrounding loops. Our study reveals the structural details of the DSE mechanism.
Collapse
|
4
|
Domain activities of PapC usher reveal the mechanism of action of an Escherichia coli molecular machine. Proc Natl Acad Sci U S A 2012; 109:9563-8. [PMID: 22645361 DOI: 10.1073/pnas.1207085109] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
P pili are prototypical chaperone-usher pathway-assembled pili used by Gram-negative bacteria to adhere to host tissues. The PapC usher contains five functional domains: a transmembrane β-barrel, a β-sandwich Plug, an N-terminal (periplasmic) domain (NTD), and two C-terminal (periplasmic) domains, CTD1 and CTD2. Here, we delineated usher domain interactions between themselves and with chaperone-subunit complexes and showed that overexpression of individual usher domains inhibits pilus assembly. Prior work revealed that the Plug domain occludes the pore of the transmembrane domain of a solitary usher, but the chaperone-adhesin-bound usher has its Plug displaced from the pore, adjacent to the NTD. We demonstrate an interaction between the NTD and Plug domains that suggests a biophysical basis for usher gating. Furthermore, we found that the NTD exhibits high-affinity binding to the chaperone-adhesin (PapDG) complex and low-affinity binding to the major tip subunit PapE (PapDE). We also demonstrate that CTD2 binds with lower affinity to all tested chaperone-subunit complexes except for the chaperone-terminator subunit (PapDH) and has a catalytic role in dissociating the NTD-PapDG complex, suggesting an interplay between recruitment to the NTD and transfer to CTD2 during pilus initiation. The Plug domain and the NTD-Plug complex bound all of the chaperone-subunit complexes tested including PapDH, suggesting that the Plug actively recruits chaperone-subunit complexes to the usher and is the sole recruiter of PapDH. Overall, our studies reveal the cooperative, active roles played by periplasmic domains of the usher to initiate, grow, and terminate a prototypical chaperone-usher pathway pilus.
Collapse
|
5
|
Chen FJ, Chan CH, Huang YJ, Liu KL, Peng HL, Chang HY, Liou GG, Yew TR, Liu CH, Hsu KY, Hsu L. Structural and mechanical properties of Klebsiella pneumoniae type 3 Fimbriae. J Bacteriol 2011; 193:1718-25. [PMID: 21239584 PMCID: PMC3067671 DOI: 10.1128/jb.01395-10] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2010] [Accepted: 01/06/2011] [Indexed: 11/20/2022] Open
Abstract
This study investigated the structural and mechanical properties of Klebsiella pneumoniae type 3 fimbriae, which constitute a known virulence factor for the bacterium. Transmission electron microscopy and optical tweezers were used to understand the ability of the bacterium to survive flushes. An individual K. pneumoniae type 3 fimbria exhibited a helix-like structure with a pitch of 4.1 nm and a three-phase force-extension curve. The fimbria was first nonlinearly stretched with increasing force. Then, it started to uncoil and extended several micrometers at a fixed force of 66 ± 4 pN (n = 22). Finally, the extension of the fimbria shifted to the third phase, with a characteristic force of 102 ± 9 pN (n = 14) at the inflection point. Compared with the P fimbriae and type 1 fimbriae of uropathogenic Escherichia coli, K. pneumoniae type 3 fimbriae have a larger pitch in the helix-like structure and stronger uncoiling and characteristic forces.
Collapse
Affiliation(s)
- Feng-Jung Chen
- Institute and Department of Electrophysics, Department of Photonics and Institute of Electro-Optical Engineering, Department of Biological Science and Technology, National Chiao Tung University, 1001 University Road, Hsinchu 300, Taiwan, Republic of China, Department of Materials Science and Engineering, Institute of Molecular Medicine and Department of Life Sciences, Department of Power Mechanical Engineering, National Tsing Hua University, 101, Section 2, Kuang-Fu Road, Hsinchu 300, Taiwan, Republic of China, Division of Molecular and Genomic Medicine, National Health Research Institutes, 35 Keyan Road, Jhunan, Miaoli County 350, Taiwan, Republic of China
| | - Chia-Han Chan
- Institute and Department of Electrophysics, Department of Photonics and Institute of Electro-Optical Engineering, Department of Biological Science and Technology, National Chiao Tung University, 1001 University Road, Hsinchu 300, Taiwan, Republic of China, Department of Materials Science and Engineering, Institute of Molecular Medicine and Department of Life Sciences, Department of Power Mechanical Engineering, National Tsing Hua University, 101, Section 2, Kuang-Fu Road, Hsinchu 300, Taiwan, Republic of China, Division of Molecular and Genomic Medicine, National Health Research Institutes, 35 Keyan Road, Jhunan, Miaoli County 350, Taiwan, Republic of China
| | - Ying-Jung Huang
- Institute and Department of Electrophysics, Department of Photonics and Institute of Electro-Optical Engineering, Department of Biological Science and Technology, National Chiao Tung University, 1001 University Road, Hsinchu 300, Taiwan, Republic of China, Department of Materials Science and Engineering, Institute of Molecular Medicine and Department of Life Sciences, Department of Power Mechanical Engineering, National Tsing Hua University, 101, Section 2, Kuang-Fu Road, Hsinchu 300, Taiwan, Republic of China, Division of Molecular and Genomic Medicine, National Health Research Institutes, 35 Keyan Road, Jhunan, Miaoli County 350, Taiwan, Republic of China
| | - Kuo-Liang Liu
- Institute and Department of Electrophysics, Department of Photonics and Institute of Electro-Optical Engineering, Department of Biological Science and Technology, National Chiao Tung University, 1001 University Road, Hsinchu 300, Taiwan, Republic of China, Department of Materials Science and Engineering, Institute of Molecular Medicine and Department of Life Sciences, Department of Power Mechanical Engineering, National Tsing Hua University, 101, Section 2, Kuang-Fu Road, Hsinchu 300, Taiwan, Republic of China, Division of Molecular and Genomic Medicine, National Health Research Institutes, 35 Keyan Road, Jhunan, Miaoli County 350, Taiwan, Republic of China
| | - Hwei-Ling Peng
- Institute and Department of Electrophysics, Department of Photonics and Institute of Electro-Optical Engineering, Department of Biological Science and Technology, National Chiao Tung University, 1001 University Road, Hsinchu 300, Taiwan, Republic of China, Department of Materials Science and Engineering, Institute of Molecular Medicine and Department of Life Sciences, Department of Power Mechanical Engineering, National Tsing Hua University, 101, Section 2, Kuang-Fu Road, Hsinchu 300, Taiwan, Republic of China, Division of Molecular and Genomic Medicine, National Health Research Institutes, 35 Keyan Road, Jhunan, Miaoli County 350, Taiwan, Republic of China
| | - Hwan-You Chang
- Institute and Department of Electrophysics, Department of Photonics and Institute of Electro-Optical Engineering, Department of Biological Science and Technology, National Chiao Tung University, 1001 University Road, Hsinchu 300, Taiwan, Republic of China, Department of Materials Science and Engineering, Institute of Molecular Medicine and Department of Life Sciences, Department of Power Mechanical Engineering, National Tsing Hua University, 101, Section 2, Kuang-Fu Road, Hsinchu 300, Taiwan, Republic of China, Division of Molecular and Genomic Medicine, National Health Research Institutes, 35 Keyan Road, Jhunan, Miaoli County 350, Taiwan, Republic of China
| | - Gunn-Guang Liou
- Institute and Department of Electrophysics, Department of Photonics and Institute of Electro-Optical Engineering, Department of Biological Science and Technology, National Chiao Tung University, 1001 University Road, Hsinchu 300, Taiwan, Republic of China, Department of Materials Science and Engineering, Institute of Molecular Medicine and Department of Life Sciences, Department of Power Mechanical Engineering, National Tsing Hua University, 101, Section 2, Kuang-Fu Road, Hsinchu 300, Taiwan, Republic of China, Division of Molecular and Genomic Medicine, National Health Research Institutes, 35 Keyan Road, Jhunan, Miaoli County 350, Taiwan, Republic of China
| | - Tri-Rung Yew
- Institute and Department of Electrophysics, Department of Photonics and Institute of Electro-Optical Engineering, Department of Biological Science and Technology, National Chiao Tung University, 1001 University Road, Hsinchu 300, Taiwan, Republic of China, Department of Materials Science and Engineering, Institute of Molecular Medicine and Department of Life Sciences, Department of Power Mechanical Engineering, National Tsing Hua University, 101, Section 2, Kuang-Fu Road, Hsinchu 300, Taiwan, Republic of China, Division of Molecular and Genomic Medicine, National Health Research Institutes, 35 Keyan Road, Jhunan, Miaoli County 350, Taiwan, Republic of China
| | - Cheng-Hsien Liu
- Institute and Department of Electrophysics, Department of Photonics and Institute of Electro-Optical Engineering, Department of Biological Science and Technology, National Chiao Tung University, 1001 University Road, Hsinchu 300, Taiwan, Republic of China, Department of Materials Science and Engineering, Institute of Molecular Medicine and Department of Life Sciences, Department of Power Mechanical Engineering, National Tsing Hua University, 101, Section 2, Kuang-Fu Road, Hsinchu 300, Taiwan, Republic of China, Division of Molecular and Genomic Medicine, National Health Research Institutes, 35 Keyan Road, Jhunan, Miaoli County 350, Taiwan, Republic of China
| | - Ken Y. Hsu
- Institute and Department of Electrophysics, Department of Photonics and Institute of Electro-Optical Engineering, Department of Biological Science and Technology, National Chiao Tung University, 1001 University Road, Hsinchu 300, Taiwan, Republic of China, Department of Materials Science and Engineering, Institute of Molecular Medicine and Department of Life Sciences, Department of Power Mechanical Engineering, National Tsing Hua University, 101, Section 2, Kuang-Fu Road, Hsinchu 300, Taiwan, Republic of China, Division of Molecular and Genomic Medicine, National Health Research Institutes, 35 Keyan Road, Jhunan, Miaoli County 350, Taiwan, Republic of China
| | - Long Hsu
- Institute and Department of Electrophysics, Department of Photonics and Institute of Electro-Optical Engineering, Department of Biological Science and Technology, National Chiao Tung University, 1001 University Road, Hsinchu 300, Taiwan, Republic of China, Department of Materials Science and Engineering, Institute of Molecular Medicine and Department of Life Sciences, Department of Power Mechanical Engineering, National Tsing Hua University, 101, Section 2, Kuang-Fu Road, Hsinchu 300, Taiwan, Republic of China, Division of Molecular and Genomic Medicine, National Health Research Institutes, 35 Keyan Road, Jhunan, Miaoli County 350, Taiwan, Republic of China
| |
Collapse
|
6
|
Structural homology between the C-terminal domain of the PapC usher and its plug. J Bacteriol 2010; 192:1824-31. [PMID: 20118254 DOI: 10.1128/jb.01677-09] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
P pili are extracellular appendages responsible for the targeting of uropathogenic Escherichia coli to the kidney. They are assembled by the chaperone-usher (CU) pathway of pilus biogenesis involving two proteins, the periplasmic chaperone PapD and the outer membrane assembly platform, PapC. Many aspects of the structural biology of the Pap CU pathway have been elucidated, except for the C-terminal domain of the PapC usher, the structure of which is unknown. In this report, we identify a stable and folded fragment of the C-terminal region of the PapC usher and determine its structure using both X-ray crystallography and nuclear magnetic resonance (NMR) spectroscopy. These structures reveal a beta-sandwich fold very similar to that of the plug domain, a domain of PapC obstructing its translocation domain. This structural similarity suggests similar functions in usher-mediated pilus biogenesis, playing out at different stages of the process. This structure paves the way for further functional analysis targeting surfaces common to both the plug and the C-terminal domain of PapC.
Collapse
|
7
|
Lee YM, Dodson KW, Hultgren SJ. Adaptor function of PapF depends on donor strand exchange in P-pilus biogenesis of Escherichia coli. J Bacteriol 2007; 189:5276-83. [PMID: 17496084 PMCID: PMC1951870 DOI: 10.1128/jb.01648-06] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
P-pilus biogenesis occurs via the highly conserved chaperone-usher pathway and involves the strict coordination of multiple subunit proteins. All nonadhesin structural P-pilus subunits possess the same topology, consisting of two domains: an incomplete immunoglobulin-like fold (pilin body) and an N-terminal extension. Pilus subunits form interactions with one another through donor strand exchange, occurring at the usher, in which the N-terminal extension of an incoming subunit completes the pilin body of the preceding subunit, allowing the incorporation of the subunit into the pilus fiber. In this study, pilus subunits in which the N-terminal extension was either deleted or swapped with that of another subunit were used to examine the role of each domain of PapF in functions involving donor strand exchange and hierarchical assembly. We found that the N-terminal extension of PapF is required to adapt the PapG adhesin to the tip of the fiber. The pilin body of PapF is required to efficiently initiate assembly of the remainder of the pilus, with the assistance of the N-terminal extension. Thus, distinct functions were assigned to each region of the PapF subunit. In conclusion, all pilin subunits possess the same overall architectural topology; however, each N-terminal extension and pilin body has specific functions in pilus biogenesis.
Collapse
Affiliation(s)
- Yvonne M Lee
- Department of Molecular Microbiology, Washington University School of Medicine, 660 South Euclid Ave., Campus Box 8230, St. Louis, MO 63110, USA
| | | | | |
Collapse
|
8
|
Mu XQ, Bullitt E. Structure and assembly of P-pili: a protruding hinge region used for assembly of a bacterial adhesion filament. Proc Natl Acad Sci U S A 2006; 103:9861-6. [PMID: 16782819 PMCID: PMC1502544 DOI: 10.1073/pnas.0509620103] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
High-resolution structures of macromolecular complexes offer unparalleled insight into the workings of biological systems and hence the interplay of these systems in health and disease. We have adopted a multifaceted approach to understanding the pathogenically important structure of P-pili, the class I adhesion pili from pyelonephritic Escherichia coli. Our approach combines electron cryomicroscopy, site-directed mutagenesis, homology modeling, and energy calculations, resulting in a high-resolution model of PapA, the major structural element of these pili. Fitting of the modeled PapA subunit into the electron cryomicroscopy data provides a detailed view of these pilins within the supramolecular architecture of the pilus filament. A structural hinge in the N-terminal region of the subunit is located at the site of a newly resolved electron density that protrudes from the P-pilus surface. The structural flexibility provided by this hinge is necessary for assembly of P-pili, illustrating one solution to construction of large macromolecular complexes from small repeating units. These data support our hypothesis that domain-swapped pilin subunits transit the outer cell membrane vertically and rotate about the hinge for final positioning into the pilus filament. Our data confirm and supply a structural basis for much previous genetic, biochemical, and structural data. This model of the P-pilus filament provides an insight into the mechanism of assembly of a macromolecular complex essential for initiation of kidney infection by these bacteria.
Collapse
Affiliation(s)
- Xiang-Qi Mu
- Department of Physiology and Biophysics, Boston University School of Medicine, Boston, MA 02118
| | - Esther Bullitt
- Department of Physiology and Biophysics, Boston University School of Medicine, Boston, MA 02118
- *To whom correspondence should be addressed at:
Department of Physiology and Biophysics, Boston University School of Medicine, 715 Albany Street, W302, Boston, MA 02118-2526. E-mail:
| |
Collapse
|
9
|
Simons BL, Rathman P, Malij CR, Oudega B, Graaf FK. The penultimate tyrosine residue of the K99 fibrillar subunit is essential for stability of the protein and its interaction with the periplasmic carrier protein. FEMS Microbiol Lett 2006. [DOI: 10.1111/j.1574-6968.1990.tb13845.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
|
10
|
Verdonck F, Cox E, Goddeeris BM. F4 fimbriae expressed by porcine enterotoxigenic Escherichia coli, an example of an eccentric fimbrial system? J Mol Microbiol Biotechnol 2004; 7:155-69. [PMID: 15383714 DOI: 10.1159/000079825] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
An overwhelming number of infectious diseases in both humans and animals are initiated by bacterial adhesion to carbohydrate structures on a mucosal surface. Most bacterial pathogens mediate this adhesion by fimbriae or pili which contain an adhesive lectin subunit. The importance of fimbriae as virulence factors led to research elucidating the regulation of fimbrial expression and their molecular assembly process. This review provides an overview of the current knowledge of induction, expression and assembly of F4 (K88) fimbriae and discusses its unique as well as its identical characteristics compared to other intensively studied fimbriae or pili expressed by Escherichia coli.
Collapse
Affiliation(s)
- F Verdonck
- Laboratory of Veterinary Immunology, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium.
| | | | | |
Collapse
|
11
|
Lee YM, DiGiuseppe PA, Silhavy TJ, Hultgren SJ. P pilus assembly motif necessary for activation of the CpxRA pathway by PapE in Escherichia coli. J Bacteriol 2004; 186:4326-37. [PMID: 15205435 PMCID: PMC421624 DOI: 10.1128/jb.186.13.4326-4337.2004] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
P pilus biogenesis occurs via the highly conserved chaperone-usher pathway, and assembly is monitored by the CpxRA two-component signal transduction pathway. Structural pilus subunits consist of an N-terminal extension followed by an incomplete immunoglobulin-like fold that is missing a C-terminal seventh beta strand. In the pilus fiber, the immunoglobulin-like fold of each pilin is completed by the N-terminal extension of its neighbor. Subunits that do not get incorporated into the pilus fiber are driven "OFF-pathway." In this study, we found that PapE was the only OFF-pathway nonadhesin P pilus subunit capable of activating Cpx. Manipulation of the PapE structure by removing, relocating within the protein, or swapping its N-terminal extension with that of other subunits altered the protein's self-associative and Cpx-activating properties. The self-association properties of the new subunits were dictated by the specific N-terminal extension provided and were consistent with the order of the subunits in the pilus fiber. However, these aggregation properties did not directly correlate with Cpx induction. Cpx activation instead correlated with the presence or absence of an N-terminal extension in the PapE pilin structure. Removal of the N-terminal extension of PapE was sufficient to abolish Cpx activation. Replacement of an N-terminal extension at either the amino or carboxyl terminus restored Cpx induction. Thus, the data presented in this study argue that PapE has features inherent in its structure or during its folding that act as specific inducers of Cpx signal transduction.
Collapse
Affiliation(s)
- Yvonne M Lee
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, Missouri 63110, USA
| | | | | | | |
Collapse
|
12
|
Aras RA, Fischer W, Perez-Perez GI, Crosatti M, Ando T, Haas R, Blaser MJ. Plasticity of repetitive DNA sequences within a bacterial (Type IV) secretion system component. J Exp Med 2003; 198:1349-60. [PMID: 14581606 PMCID: PMC2194252 DOI: 10.1084/jem.20030381] [Citation(s) in RCA: 74] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2003] [Revised: 07/23/2003] [Accepted: 09/22/2003] [Indexed: 12/13/2022] Open
Abstract
DNA rearrangement permits bacteria to regulate gene content and expression. In Helicobacter pylori, cagY, which contains an extraordinary number of direct DNA repeats, encodes a surface-exposed subunit of a (type IV) bacterial secretory system. Examining potential DNA rearrangements involving the cagY repeats indicated that recombination events invariably yield in-frame open reading frames, producing alternatively expressed genes. In individual hosts, H. pylori cell populations include strains that produce CagY proteins that differ in size, due to the predicted in-frame deletions or duplications, and elicit minimal or no host antibody recognition. Using repetitive DNA, H. pylori rearrangements in a host-exposed subunit of a conserved bacterial secretion system may permit a novel form of antigenic evasion.
Collapse
Affiliation(s)
- Rahul A Aras
- Department of Medicine, New York University School of Medicine, and VA Medical Center, NY 10016, USA.
| | | | | | | | | | | | | |
Collapse
|
13
|
Lügering A, Benz I, Knochenhauer S, Ruffing M, Schmidt MA. The Pix pilus adhesin of the uropathogenic Escherichia coli strain X2194 (O2 : K(-): H6) is related to Pap pili but exhibits a truncated regulatory region. MICROBIOLOGY (READING, ENGLAND) 2003; 149:1387-1397. [PMID: 12777480 DOI: 10.1099/mic.0.26266-0] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Adhesins provide a major advantage for uropathogenic Escherichia coli in establishing urinary tract infections (UTIs). A novel gene cluster responsible for the expression of a filamentous adhesin of the pyelonephritogenic E. coli strain X2194 has been identified, molecularly cloned, and characterized. The 'pix operon' contains eight open reading frames which exhibit significant sequence homology to corresponding genes in the pap operon encoding P pili, the prevalent E. coli adhesins in non-obstructive acute pyelonephritis in humans. Although a pixB gene corresponding to the PapB regulator was identified, a papI homologue could not be found in the pix operon. Instead, a fragment of the R6 gene of the highly uropathogenic E. coli strain CFT073 was identified upstream of pixB. The R6 gene is located in a pathogenicity island containing several pilus-encoding sequences and shows homology to a transposase of Chelatobacter heintzii. In a pixA-lacZ fusion system it was demonstrated that the expression of Pix pili is regulated at the transcriptional level by the R6 gene sequence. A significantly reduced transcription was observed by deleting this fragment and by lowering the growth temperature from 37 to 26 degrees C. In contrast to other filamentous adhesin systems, Pix pili are mainly expressed in the steady state growth phase and were not repressed by the addition of glucose.
Collapse
MESH Headings
- Adhesins, Escherichia coli/genetics
- Adhesins, Escherichia coli/physiology
- Amino Acid Sequence
- Base Sequence
- Cloning, Molecular
- DNA, Bacterial/genetics
- Escherichia coli/genetics
- Escherichia coli/pathogenicity
- Escherichia coli/physiology
- Escherichia coli/ultrastructure
- Escherichia coli Infections/etiology
- Fimbriae Proteins/genetics
- Fimbriae Proteins/physiology
- Fimbriae, Bacterial/physiology
- Fimbriae, Bacterial/ultrastructure
- Gene Expression Regulation, Bacterial
- Genes, Bacterial
- Genes, Regulator
- HeLa Cells
- Humans
- Microscopy, Electron
- Molecular Sequence Data
- Multigene Family
- Operon
- Pyelonephritis/etiology
- Sequence Homology, Amino Acid
- Temperature
- Virulence/genetics
Collapse
Affiliation(s)
- Andreas Lügering
- Institut für Infektiologie, Zentrum für Molekularbiologie der Entzündung (ZMBE), Von Esmarch Strasse 56, Westfälische Wilhelms-Universität Münster, D-48149 Münster, Germany
| | - Inga Benz
- Institut für Infektiologie, Zentrum für Molekularbiologie der Entzündung (ZMBE), Von Esmarch Strasse 56, Westfälische Wilhelms-Universität Münster, D-48149 Münster, Germany
| | - Sabine Knochenhauer
- Institut für Infektiologie, Zentrum für Molekularbiologie der Entzündung (ZMBE), Von Esmarch Strasse 56, Westfälische Wilhelms-Universität Münster, D-48149 Münster, Germany
| | - Michael Ruffing
- Institut für Infektiologie, Zentrum für Molekularbiologie der Entzündung (ZMBE), Von Esmarch Strasse 56, Westfälische Wilhelms-Universität Münster, D-48149 Münster, Germany
| | - M Alexander Schmidt
- Institut für Infektiologie, Zentrum für Molekularbiologie der Entzündung (ZMBE), Von Esmarch Strasse 56, Westfälische Wilhelms-Universität Münster, D-48149 Münster, Germany
| |
Collapse
|
14
|
Tito MA, Miller J, Griffin KF, Williamson ED, Titball RW, Robinson CV. Macromolecular organization of the Yersinia pestis capsular F1 antigen: insights from time-of-flight mass spectrometry. Protein Sci 2001; 10:2408-13. [PMID: 11604546 PMCID: PMC2374054 DOI: 10.1110/ps.11101] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
Mass spectrometry has been used to examine the subunit interactions in the capsular F1 antigen from Yersinia pestis, the causative agent of the plague. Introducing the sample using nanoflow electrospray from solution conditions in which the protein remains in its native state and applying collisional cooling to minimize the internal energy of the ions, multiple subunit interactions have been maintained. This methodology revealed assemblies of the F1 antigen that correspond in mass to both 7-mers and 14-mers, consistent with interaction of two seven-membered units. The difference between the calculated masses and those measured experimentally for these higher-order oligomers was found to increase proportionately with the size of the complex. This is consistent with a solvent-filled central cavity maintained on association of the 7-mer to the 14-mer. The charge states of the ions show that an average of one and four surface accessible basic side-chains are involved in maintaining the interactions between the 7-mer units and neighboring subunits, respectively. Taken together, these findings provide new information about the stoichiometry and packing of the subunits involved in the assembly of the capsular antigen structure. More generally, the data show that the symmetry and packing of macromolecular complexes can be determined solely from mass spectrometry, without any prior knowledge of higher order structure
Collapse
Affiliation(s)
- M A Tito
- Oxford Centre for Molecular Sciences, New Chemistry Laboratory, Oxford, OX1 3QT, United Kingdom
| | | | | | | | | | | |
Collapse
|
15
|
Pouttu R, Westerlund-Wikström B, Lång H, Alsti K, Virkola R, Saarela U, Siitonen A, Kalkkinen N, Korhonen TK. matB, a common fimbrillin gene of Escherichia coli, expressed in a genetically conserved, virulent clonal group. J Bacteriol 2001; 183:4727-36. [PMID: 11466275 PMCID: PMC99526 DOI: 10.1128/jb.183.16.4727-4736.2001] [Citation(s) in RCA: 61] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
A novel fimbrial type in Escherichia coli was identified and characterized. The expression of the fimbria was associated with the O18acK1H7 clonal group of E. coli, which cause newborn meningitis and septicemia when grown at low temperature; hence, it was named the Mat (meningitis associated and temperature regulated) fimbria. The fimbriae were purified from a fimA::cat sfaA::Gm fliC::St derivative of the O18K1H7 isolate E. coli IHE 3034. The purified Mat fimbrillin had an apparent molecular mass of 18 kDa and did not serologically cross-react with the type 1 or S fimbria of the same strain. The matB gene encoding the major fimbrillin was cloned from the genomic DNA of the fimA::cat sfaA::Gm fliC::St derivative of IHE 3034. The predicted MatB sequence was of 195 amino acids, contained a signal sequence of 22 residues, and did not show significant homology to any of the previously characterized fimbrial proteins. The DNA sequence of matB was 97.8% identical to a region from nucleotides 17882 to 18469 in the 6- to 8-min region of the E. coli K-12 chromosome, reported to encode a hypothetical protein. The 7-kb DNA fragment containing matB of IHE 3034 was found by restriction mapping and partial DNA sequencing to be highly similar to the corresponding region in the K-12 chromosome. Trans complementation of the matB::cat mutation in the IHE 3034 chromosome showed that matB in combination with matA or matC restored surface expression of the Mat fimbria. A total of 27 isolates representing K-12 strains and the major pathogroups of E. coli were analyzed for the presence of a matB homolog as well as for expression of the Mat fimbria. A conserved matB homolog was found in 25 isolates; however, expression of the Mat fimbriae was detected only in the O18acK1H7 isolates. Expression of the Mat fimbria was temperature regulated, with no or a very small amount of fimbriae or intracellular MatB fimbrillin being detected in cells cultivated at 37(o)C. Reverse transcriptase PCR and complementation assays with mat genes controlled by the inducible trc promoter indicated that regulation of Mat fimbria expression involved both transcriptional and posttranscriptional events.
Collapse
Affiliation(s)
- R Pouttu
- Division of General Microbiology, Department of Biosciences, FIN-00014 University of Helsinki, FIN-00300 Helsinki, Finland
| | | | | | | | | | | | | | | | | |
Collapse
|
16
|
Affiliation(s)
- V T Lee
- Department of Microbiology & Immunology, UCLA School of Medicine, Los Angeles, California 90095, USA.
| | | |
Collapse
|
17
|
Hung DL, Raivio TL, Jones C, Silhavy TJ, Hultgren SJ. Cpx signaling pathway monitors biogenesis and affects assembly and expression of P pili. EMBO J 2001; 20:1508-18. [PMID: 11285215 PMCID: PMC145513 DOI: 10.1093/emboj/20.7.1508] [Citation(s) in RCA: 148] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
P pili are important virulence factors in uropathogenic Escherichia coli. The Cpx two-component signal transduction system controls a stress response and is activated by misfolded proteins in the periplasm. We have discovered new functions for the Cpx pathway, indicating that it may play a critical role in pathogenesis. P pili are assembled via the chaperone/usher pathway. Subunits that go 'OFF-pathway' during pilus biogenesis generate a signal. This signal is derived from the misfolding and aggregation of subunits that failed to come into contact with the chaperone in the periplasm. In response, Cpx not only controls the stress response, but also controls genes necessary for pilus biogenesis, and is involved in regulating the phase variation of pap expression and, potentially, the expression of a panoply of other virulence factors. This study demonstrates how the prototypic chaperone/usher pathway is intricately linked and dependent upon a signal transduction system.
Collapse
Affiliation(s)
| | - Tracy L. Raivio
- Department of Molecular Microbiology, Box 8230, Washington University School of Medicine, 660 S. Euclid Avenue, St Louis, MO 63110,
SIGA Technologies Inc., 4575 SW Research Way, Suite 230, Corvallis, OR 97333, Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA and Department of Biological Sciences, 6315 Biological Services Building, University of Alberta, Edmonton, Alberta, Canada T6G 2E9 Corresponding author e-mail:
| | - C.Hal Jones
- Department of Molecular Microbiology, Box 8230, Washington University School of Medicine, 660 S. Euclid Avenue, St Louis, MO 63110,
SIGA Technologies Inc., 4575 SW Research Way, Suite 230, Corvallis, OR 97333, Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA and Department of Biological Sciences, 6315 Biological Services Building, University of Alberta, Edmonton, Alberta, Canada T6G 2E9 Corresponding author e-mail:
| | - Thomas J. Silhavy
- Department of Molecular Microbiology, Box 8230, Washington University School of Medicine, 660 S. Euclid Avenue, St Louis, MO 63110,
SIGA Technologies Inc., 4575 SW Research Way, Suite 230, Corvallis, OR 97333, Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA and Department of Biological Sciences, 6315 Biological Services Building, University of Alberta, Edmonton, Alberta, Canada T6G 2E9 Corresponding author e-mail:
| | - Scott J. Hultgren
- Department of Molecular Microbiology, Box 8230, Washington University School of Medicine, 660 S. Euclid Avenue, St Louis, MO 63110,
SIGA Technologies Inc., 4575 SW Research Way, Suite 230, Corvallis, OR 97333, Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA and Department of Biological Sciences, 6315 Biological Services Building, University of Alberta, Edmonton, Alberta, Canada T6G 2E9 Corresponding author e-mail:
| |
Collapse
|
18
|
Guyer DM, Henderson IR, Nataro JP, Mobley HL. Identification of sat, an autotransporter toxin produced by uropathogenic Escherichia coli. Mol Microbiol 2000; 38:53-66. [PMID: 11029690 DOI: 10.1046/j.1365-2958.2000.02110.x] [Citation(s) in RCA: 131] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Urinary tract infection (UTI) is a very common extraintestinal infection, and Escherichia coli is by far the most common causative organism. Uropathogenic E. coli possess traits that distinguish them from commensal strains of E. coli, such as secretion systems that allow virulence factors to be targeted to extracytoplasmic compartments. One of at least five characterized secretion mechanisms is the autotransporter system, which involves translocation of a protein across the inner membrane, presumably via the sec system, and across the outer membrane through a beta-barrel porin structure formed by the carboxy-terminus autotransporter domain. We identified a 107 kDa protein that was expressed significantly more often by E. coli strains associated with the clinical syndrome of acute pyelonephritis than by faecal strains (P = 0.029). We isolated the protein from E. coli CFT073, a strain cultured from the blood and urine of a patient with acute pyelonephritis. The N-terminal amino acid sequence showed highest similarity to two known SPATE (serine protease autotransporters of Enterobacteriaceae) proteins, Pet and EspC. Using a 509 bp probe from the 5' region of pet, 10 cosmid clones of an E. coli CFT073 gene library were positive for hybridization. From one cosmid clone, a 7.5 kb EcoRI restriction fragment, which reacted strongly with the probe, was shown to include the entire 3885 bp gene. The predicted 142 kDa protein product possesses the three domains that are typical of SPATE autotransporters: an unusually long signal sequence of 49 amino acids; a 107 kDa passenger domain containing a consensus serine protease active site (GDSGSG); and a C-terminal autotransporter domain of 30 kDa. The protein exhibited serine protease activity and displayed cytopathic activity on VERO primary kidney, HK-2 bladder and HEp-2 cell lines; the name Sat (secreted autotransporter toxin) was derived from these properties. In addition, Sat antibodies were present in the serum of mice infected with E. coli CFT073. Based upon its association with pathogenic isolates, its cytopathic phenotype and its ability to elicit a strong antibody response after infection, we postulate that Sat represents a novel virulence determinant of uropathogenic E. coli.
Collapse
Affiliation(s)
- D M Guyer
- Department of Microbiology and Immunology, and Center for Vaccine Development, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | | | | | | |
Collapse
|
19
|
Bertin Y, Girardeau JP, Darfeuille-Michaud A, Martin C. Epidemiological study of pap genes among diarrheagenic or septicemic Escherichia coli strains producing CS31A and F17 adhesins and characterization of Pap(31A) fimbriae. J Clin Microbiol 2000; 38:1502-9. [PMID: 10747134 PMCID: PMC86476 DOI: 10.1128/jcm.38.4.1502-1509.2000] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The association of the pap operon with the CS31A and F17 adhesins was studied with 255 Escherichia coli strains isolated from calves, lambs, or humans with diarrhea. The three classes of PapG adhesin with different receptor binding preferences were also screened. The pap operon was associated with 50 and 36% of human strains that produced CS31A and ovine strains that produced F17, respectively. Among the bovine isolates, the pap operon was detected in 61% of the CS31A-positive isolates and 72% of the strains that produce both CS31A and F17. The class II adhesin gene was present in bovine (20%) and ovine (71%) isolates. Both class II and III adhesins were genetically associated with 36% of the human strains. The highest prevalence of the pap operon was observed among E. coli strains that produce additional adhesins involved in the binding of bacteria to intestinal cells. Among the bovine isolates, the reference strain for CS31A and F17c was found to be positive for the pap operon. Phenotypic and genotypic characterizations were undertaken. Pap(31A) appeared as fine and flexible fimbriae surrounding the bacteria but did not mediate adhesion to calf intestinal villi. Pap(31A) production was optimal with bacteria cultured on minimal growth media and repressed by addition of exogenous leucine. The deduced amino acid sequence of the PapA(31A) structural subunit showed 57 to 97% identity with the different P-related structural subunits produced by E. coli strains isolated from pigs with septicemia or humans with urinary tract infections. None of the three papG allelic variants was detected, but a homologous papG gene was present in the chromosome of strain 31A.
Collapse
Affiliation(s)
- Y Bertin
- Laboratoire de Microbiologie, Centre de Recherche, INRA de Clermont-Ferrand-Theix, 63122 St-Genès Champanelle, France.
| | | | | | | |
Collapse
|
20
|
Johnson JR, Stell AL, Scheutz F, O'Bryan TT, Russo TA, Carlino UB, Fasching C, Kavle J, Van Dijk L, Gaastra W. Analysis of the F antigen-specific papA alleles of extraintestinal pathogenic Escherichia coli using a novel multiplex PCR-based assay. Infect Immun 2000; 68:1587-99. [PMID: 10678978 PMCID: PMC97319 DOI: 10.1128/iai.68.3.1587-1599.2000] [Citation(s) in RCA: 67] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/1999] [Accepted: 12/15/1999] [Indexed: 11/20/2022] Open
Abstract
Polymorphisms in PapA, the major structural subunit and antigenic determinant of P fimbriae of extraintestinal pathogenic Escherichia coli, are of considerable epidemiological, phylogenetic, and immunotherapeutic importance. However, to date, no method other than DNA sequencing has been generally available for their detection. In the present study, we developed and rigorously validated a novel PCR-based assay for the 11 recognized variants of papA and then used the new assay to assess the prevalence, phylogenetic distribution, and bacteriological associations of the papA alleles among 75 E. coli isolates from patients with urosepsis. In comparison with conventional F serotyping, the assay was extremely sensitive and specific, evidence that papA sequences are highly conserved within each of the traditionally recognized F serotypes despite the diversity observed among F types. In certain strains, the assay detected serologically occult copies of papA, of which some were shown to represent false-negative serological results and others were shown to represent the presence of nonfunctional pap fragments. Among the urosepsis isolates, the assay revealed considerable segregation of papA alleles according to O:K:H serotype, consistent with vertical transmission within clones, but with exceptions which strongly suggested horizontal transfer of papA alleles between lineages. Sequencing of papA from two strains that were papA positive by probe and PCR but F negative in the new PCR assay led to the discovery of two novel papA variants, one of which was actually more prevalent among the urosepsis isolates than were several of the known papA alleles. These findings provide novel insights into the papA alleles of extraintestinal pathogenic E. coli and indicate that the F PCR assay represents a versatile new molecular tool for epidemiological and phylogenetic investigations which should make rapid, specific detection of papA alleles available to any laboratory with PCR capability.
Collapse
Affiliation(s)
- J R Johnson
- Medical Service, VA Medical Center, and Department of Medicine, University of Minnesota, Minneapolis, Minnesota, USA.
| | | | | | | | | | | | | | | | | | | |
Collapse
|
21
|
Abstract
PapD is the periplasmic chaperone required for the assembly of P pili in pyelonephritic strains of Escherichia coli. It consists of two immunoglobulin-like domains bisected by a subunit binding cleft. PapD is the prototype member of a super family of immunoglobulin-like chaperones that work in concert with their respective ushers to assemble a plethora of adhesive organelles including pilus- and non-pilus-associated adhesins. Three highly conserved residue clusters have been shown to play critical roles in the structure and function of PapD, as determined by site-directed mutagenesis. The in vivo stability of the chaperone depended on the formation of a buried salt bridge within the cleft. Residues along the G1 beta strand were required for efficient binding of subunits consistent with the crystal structure of PapD-peptide complexes. Finally, Thr-53, a residue that is part of a conserved band of residues located on the amino-terminal domain surface opposite the subunit binding cleft, was also found to be critical for pilus assembly, but mutations at Thr-53 did not interfere with chaperone-subunit complex formation.
Collapse
Affiliation(s)
- D L Hung
- Department of Molecular Microbiology, Washington University School of Medicine, St Louis, MO 63110, USA
| | | | | |
Collapse
|
22
|
Hung DL, Hultgren SJ. Pilus biogenesis via the chaperone/usher pathway: an integration of structure and function. J Struct Biol 1998; 124:201-20. [PMID: 10049807 DOI: 10.1006/jsbi.1998.4049] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The molecular basis of how pathogenic bacteria cause disease has been studied by blending a well-developed genetic system with X-ray crystallography, protein chemistry, high resolution electron microscopy, and cell biology. Microbial attachment to host tissues is one of the key events in the early stages of most bacterial infections. Attachment is typically mediated by adhesins that are assembled into hair-like fibers called pili on bacterial surfaces. This article focuses on the structure-function correlates of P pili, which are produced by most pyelonephritic strains of Escherichia coli. P pili are assembled via a chaperone/usher pathway. Similar pathways are responsible for the assembly of over 30 adhesive organelles in various Gram-negative pathogens. P pilus biogenesis has been used as a model system to elucidate common themes in bacterial pathogenesis, namely, the protein folding, secretion, and assembly of virulence factors. The structural basis for pilus biogenesis is discussed as well as the function and consequences of microbial attachment.
Collapse
Affiliation(s)
- D L Hung
- Department of Molecular Microbiology, Washington University, St. Louis, Missouri, 63110, USA
| | | |
Collapse
|
23
|
Guyer DM, Kao JS, Mobley HL. Genomic analysis of a pathogenicity island in uropathogenic Escherichia coli CFT073: distribution of homologous sequences among isolates from patients with pyelonephritis, cystitis, and Catheter-associated bacteriuria and from fecal samples. Infect Immun 1998; 66:4411-7. [PMID: 9712795 PMCID: PMC108533 DOI: 10.1128/iai.66.9.4411-4417.1998] [Citation(s) in RCA: 112] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/1998] [Accepted: 06/10/1998] [Indexed: 11/20/2022] Open
Abstract
Urinary tract infection is the most frequently diagnosed kidney and urologic disease and Escherichia coli is by far the most common etiologic agent. Uropathogenic strains have been shown to contain blocks of DNA termed pathogenicity islands (PAIs) which contribute to their virulence. We have defined one of these regions of DNA within the chromosome of a highly virulent E. coli strain, CFT073, isolated from the blood and urine of a woman with acute pyelonephritis. The 57,988-bp stretch of DNA has characteristics which define PAIs, including a size greater than 30 kb, the presence of insertion sequences, distinct segmentation of K-12 and J96 origin, GC content (42.9%) different from that of total genomic DNA (50.8%), and the presence of virulence genes (hly and pap). Within this region, we have identified 44 open reading frames; of these 44, 10 are homologous to entries in the complete K-12 genome sequence, 4 are nearly identical to the sequences of E. coli J96 encoding the HlyA hemolysin, 11 encode P fimbriae, and 19 show no homology to J96 or K-12 entries. To determine whether sequences found within the junctions of the PAI of CFT073 were common to other uropathogenic strains of E. coli, 11 probes were isolated along the length of the PAI and were hybridized to dot blots of genomic DNA isolated from clinical isolates (67 from patients with acute pyelonephritis, 38 from patients with cystitis, 49 from patients with catheter-associated bacteriuria, and 27 from fecal samples). These sequences were found significantly more often in strains associated with the clinical syndromes of acute pyelonephritis (79%) and cystitis (82%) than in those associated with catheter-associated bacteriuria (58%) and in fecal strains (22%) (P < 0.001). From these regions, we have identified a putative iron transport system and genes other than hly and pap that may contribute to the virulent phenotype of uropathogenic E. coli strains.
Collapse
Affiliation(s)
- D M Guyer
- Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, Maryland 21201, USA
| | | | | |
Collapse
|
24
|
Lin JW, Lin BJ, Chen HY, Weng SF. Characteristics analysis of the luzA gene encoding chaperone from Photobacterium leiognathi related to bioluminescence. Biochem Biophys Res Commun 1998; 244:838-42. [PMID: 9535753 DOI: 10.1006/bbrc.1998.8359] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Nucleotide sequence of the luzA gene (GenBank accession No. AF039303) from Photobacterium leiognathi ATCC 25521 (NCIMB 2193) has been determined, and the chaperone encoded by the luzA gene was deduced. The LuzA chaperone has a calculated M(r) 26,295 and comprises 230 amino acid residues; the hydrophobic alpha-helix N-terminal 21 amino acid residues MKKTIFALLFMSVFI SYPSFA is the leader peptide, therefore the matured LuzA chaperone has a calculated M(r) 23,871 and comprises 209 amino acid residues only. The periplasmic LuzA chaperone is the protein concerned with the protein folding, assembly and stability. The luzA gene and the related genes are closely linked to the sod gene, that encoding Cu/Zn superoxide dismutase enables to enhance bioluminescence of the lux operon; the gene order of the luzA gene and related genes is -ufo'-luzA-ufoI-ufoII-ter->-R&R'-sod-ufo-- >. In trans complementation bioluminoassays in vivo elicit that the LuzA chaperone might be not directly concerned with bioluminescence of the lux operon from P. leiognathi in E. coli, but might enable to stabilize the proteins related to bioluminescence. The unidentified ufoII gene closely linked to the luzA gene is able to enhance bioluminescence.
Collapse
Affiliation(s)
- J W Lin
- Institute of Molecular Biology, National Chung Hsing University, Taichung, Taiwan, Republic of China.
| | | | | | | |
Collapse
|
25
|
Abstract
P-pili on uropathogenic bacteria are 68-A-diameter rods typically 1 microm in length. These structures project from the outer membrane of Escherichia coli, and contain on their distal tip a thin fibrillum, 25 A in diameter and 150 A long, displaying an adhesin protein responsible for the binding of the bacterium to the surface of epithelial cells lining the urinary tract. Operationally, it is possible to identify three morphologically distinct states of the 68-A-diameter P-pili rods, based on the degree of curvature each can adopt. These states are designated "straight," "curved," and "highly curved." The rods can also be unwound to form thin "threads" that are very similar to the tip fibrillae. Electron microscope data are used to distinguish among these four morphological states and to define limits on the shapes of the pilus proteins. The mechanical properties of the PapA polymers are assessed, and implications of rod polymorphism for pilus function are discussed. A wide variety of data are considered in light of the possibility that all pilins are similar in molecular architecture, with specific differences designed to optimize their specialized functions in the pilus assembly.
Collapse
Affiliation(s)
- E Bullitt
- Department of Biophysics, Boston University School of Medicine, Massachusetts 02118-2526, USA.
| | | |
Collapse
|
26
|
Abstract
Urinary tract infections (UTI) are caused by a variety of gram-negative bacteria that ascend into the urinary tract and establish bacteriuria often at levels greater than or equal to 10(5) bacteria/ mL of urine. Escherichia coli dominate as the causative agent in all patient groups, with Staphylococcus saprophyticus as the second most common, accounting for about 10% to 30% of the infections in young adult women depending on the season. This article covers the pathogenesis and inflammatory response of UTI and the virulence factors of uropathogenic E. coli.
Collapse
Affiliation(s)
- C Svanborg
- Department of Medical Microbiology, Lund University, Sweden
| | | |
Collapse
|
27
|
Connell H, Hedlund M, Agace W, Svanborg C. Bacterial attachment to uro-epithelial cells: mechanisms and consequences. Adv Dent Res 1997; 11:50-8. [PMID: 9524442 DOI: 10.1177/08959374970110011701] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Microbial attachment to mucosal surfaces is a first step in mucosal infection. Specific interactions between microbial surface ligands and host receptors influence the distribution of microbes in their sites of infection. Adhesion has often been regarded as a sufficient end point, explaining tissue tropism and bacterial persistence at mucosal sites. Adherence, however, is also a virulence factor through which microbes gain access to host tissues, upset the integrity of the mucosal barrier, and cause disease. The induction of mucosal inflammation is one aspect of this process. Bacterial attachment to mucosal surfaces activates the production of pro-inflammatory cytokines that cause both local and systemic inflammation. Epithelial cells are one source of these cytokines. The binding of fimbrial lectins to epithelial cell receptors triggers transmembrane signaling events that upregulate cytokine-specific mRNA and increase cytokine secretion. P fimbriae that bind the globoseries of glycolipids cause the release of ceramides and activation of the ceramide signaling pathway which contributes to the IL-6 response. Spread of cytokines and other pro-inflammatory mediators from the local site contributes to the symptoms and signs of infection.
Collapse
Affiliation(s)
- H Connell
- Department of Medical Microbiology (Section for Clinical Immunology), Lund University, Sweden
| | | | | | | |
Collapse
|
28
|
Soderhall M, Bergerheim US, Jacobson SH, Lundahl J, Mollby R, Normark S, Winberg J. Molecular Evidence for Pap-G Specific Adhesion of Escherichia Coli to Human Renal Cells. J Urol 1997. [DOI: 10.1016/s0022-5347(01)65375-8] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Mats Soderhall
- Departments of Nephrology, Urology, Clinical Immunology, and Pediatrics, Karolinska Hospital, and the Microbiology and Tumor Biology Center, Karolinska Institute, Stockholm, Sweden
| | - Ulf S.R. Bergerheim
- Departments of Nephrology, Urology, Clinical Immunology, and Pediatrics, Karolinska Hospital, and the Microbiology and Tumor Biology Center, Karolinska Institute, Stockholm, Sweden
| | - Stefan H. Jacobson
- Departments of Nephrology, Urology, Clinical Immunology, and Pediatrics, Karolinska Hospital, and the Microbiology and Tumor Biology Center, Karolinska Institute, Stockholm, Sweden
| | - Joachim Lundahl
- Departments of Nephrology, Urology, Clinical Immunology, and Pediatrics, Karolinska Hospital, and the Microbiology and Tumor Biology Center, Karolinska Institute, Stockholm, Sweden
| | - Roland Mollby
- Departments of Nephrology, Urology, Clinical Immunology, and Pediatrics, Karolinska Hospital, and the Microbiology and Tumor Biology Center, Karolinska Institute, Stockholm, Sweden
| | - Staffan Normark
- Departments of Nephrology, Urology, Clinical Immunology, and Pediatrics, Karolinska Hospital, and the Microbiology and Tumor Biology Center, Karolinska Institute, Stockholm, Sweden
| | - Jan Winberg
- Departments of Nephrology, Urology, Clinical Immunology, and Pediatrics, Karolinska Hospital, and the Microbiology and Tumor Biology Center, Karolinska Institute, Stockholm, Sweden
| |
Collapse
|
29
|
Molecular Evidence for Pap-G Specific Adhesion of Escherichia Coli to Human Renal Cells. J Urol 1997. [DOI: 10.1097/00005392-199701000-00112] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
|
30
|
Mol O, Oudega B. Molecular and structural aspects of fimbriae biosynthesis and assembly in Escherichia coli. FEMS Microbiol Rev 1996; 19:25-52. [PMID: 8916554 DOI: 10.1111/j.1574-6976.1996.tb00252.x] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Fimbriae are long filamentous polymeric protein structures located at the surface of bacterial cells. They enable the bacteria to bind to specific receptor structures and thereby to colonise specific surfaces. Fimbriae consist of so-called major and minor subunits, which form, in a specific order, the fimbrial structure. In this review emphasis is put on the genetic organisation, regulation and especially on the biosynthesis of fimbriae of enterotoxigenic Escherichia coli strains, and more in particular on K88 and related fimbriae, with ample reference to well-studied P and type 1 fimbriae. The biosynthesis of these fimbriae requires two specific and unique proteins, a periplasmic chaperone and an outer membrane located molecular usher ('doorkeeper'). Molecular and structural aspects of the secretion of fimbrial subunits across the cytoplasmic membrane, the interaction of these subunits with periplasmic molecular chaperone, their translocation to the inner site of the outer membrane and their interaction with the usher protein, as well as the (ordered) translocation of the subunits across the outer membrane and their assembly into a growing fimbrial structure will be described. A model for K88 fimbriae is presented.
Collapse
Affiliation(s)
- O Mol
- Department of Molecular Microbiology, IMBW, BioCentrum Amsterdam, Faculty of Biology, The Netherlands
| | | |
Collapse
|
31
|
Di Martino P, Livrelli V, Sirot D, Joly B, Darfeuille-Michaud A. A new fimbrial antigen harbored by CAZ-5/SHV-4-producing Klebsiella pneumoniae strains involved in nosocomial infections. Infect Immun 1996; 64:2266-73. [PMID: 8675336 PMCID: PMC174065 DOI: 10.1128/iai.64.6.2266-2273.1996] [Citation(s) in RCA: 49] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
We purified and characterized a new fimbria termed KPF-28 (Klebsiella pneumoniae fimbria with a fimbrin molecular mass of 28 kDa) involved in K. pneumoniae adherence to the human carcinoma cell line Caco-2. Electron microscopy of bacterial surface protein preparations and immunogold labeling of bacterial cells showed that KPF-28 was a long, thin, and flexible fimbria about 4 to 5 nm in diameter and 0.5 to 2 microm long. The N-terminal amino acid sequence of the KPF-28 major fimbrial subunit showed no homology with type 1 and type 3 pili of K. pneumoniae but showed 61.7% identity with residues 6 to 19 of the N-terminal amino acid sequence of PapA, the Pap major pilus subunit expressed by uropathogenic Escherichia coli strains. Total amino acid content determination showed that the KPF-28 major subunit composition was close to that of the GVVPQ fimbrial family major subunits expressed by pathogenic E. coli strains. The study of the prevalence of KPF-28 among K. pneumoniae strains involved in nosocomial infections revealed that KPF-28 was found in the great majority of the K. pneumoniae strains producing the CAZ-5/SHV-4 extended-spectrum beta-lactamase. As shown by curing and mating experiments, the R plasmid encoding the CAZ-5/SHV-4 enzyme was found to be involved in but not solely responsible for KPF-28 expression. Hybridization experiments using an oligonucleotide probe corresponding to the N-terminal part of the 28-kDa protein revealed that the structural gene encoding the KPF-28 major subunit was localized on this R plasmid. KPF-28 is a putative colonization factor of the human gut, since the ceftazidine-sensitive derivative strain CF914-1C no longer adhered and since the Fab fragments of antibodies raised against KPF-28 inhibited adhesion of K. pneumoniae CF914-1 to the Caco-2 cell line.
Collapse
Affiliation(s)
- P Di Martino
- Laboratoire de Bactériologie, Facultés de Pharmacie et Médecine, Clermont-Ferrand, France
| | | | | | | | | |
Collapse
|
32
|
Gaastra W, van Oosterom RA, Pieters EW, Bergmans HE, van Dijk L, Agnes A, ter Huurne HM. Isolation and characterisation of dog uropathogenic Proteus mirabilis strains. Vet Microbiol 1996; 48:57-71. [PMID: 8701578 DOI: 10.1016/0378-1135(95)00133-6] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Proteus mirabilis strains isolated from the urine of dogs with urinary tract infections, were characterised with respect to the production of haemolysin and fimbriae. In contrast to healthy dogs, P. mirabilis was also isolated in high numbers from the faeces of dogs suffering from recurrent urinary tract infections. Production of fimbriae was demonstrated by electron microscopy and the presence of genes for two different types of major fimbrial subunits (MR/P-like or UCA-like) was demonstrated by Southern hybridisation. These genes were absent in the Proteus vulgaris, Providentia rettgeri and Morganella morganii strains tested. All but one P. mirabilis strains were haemolytic and most strains produced fimbriae albeit in different amounts. The UCA fimbrial subunits from dog and human isolates have identical molecular weights and N-terminal sequences and are immunologically cross reactive. It was concluded that dog uropathogenic P. mirabilis strains are very similar to human uropathogenic P. mirabilis strains.
Collapse
Affiliation(s)
- W Gaastra
- Institute of Infectious Diseases and Immunology, University of Utrecht, The Netherlands
| | | | | | | | | | | | | |
Collapse
|
33
|
Onoe T, Hoover CI, Nakayama K, Ideka T, Nakamura H, Yoshimura F. Identification of Porphyromonas gingivalis prefimbrilin possessing a long leader peptide: possible involvement of trypsin-like protease in fimbrilin maturation. Microb Pathog 1995; 19:351-64. [PMID: 8778568 DOI: 10.1016/s0882-4010(96)80006-4] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Fimbriae of Porphyromonas gingivalis have been shown to be important as one of the virulence factors for colonization on mucosal surfaces. The gene (fimA) encoding the fimbrial subunit (fimbrilin) was overexpressed in Escherichia coli by using a bacteriophage T7 promoter-polymerase expression vector system. Analysis of the resulting fimA gene product revealed that the prefimbrilin had a 46 amino acid leader peptide. This extremely long leader peptide was cleaved from the prefimbrilin by treatment with trypsin or P. gingivalis extracts containing trypsin-like protease activity, resulting in production of a mature fimbrilin. We also found that some transposon-induced trypsin-like protease deficient mutants of P. gingivalis exhibited deficiency in fimbriation and that one of the mutants accumulated a fimbrilin precursor possessing a 25 amino acid leader peptide in the cell. The presence of an extremely long leader peptide and the requirement for a leader peptidase with a substrate specificity similar to that of P. gingivalis trypsin-like protease for fimbrilin maturation indicate that P. gingivalis fimbrilin is a novel type that is different from fimbrilins of type I and IV families.
Collapse
Affiliation(s)
- T Onoe
- Department of Endodontics, School of Dentistry, Aichi-Gakuin University, Nagoya, Japan
| | | | | | | | | | | |
Collapse
|
34
|
Bijlsma IGW, Dijk LV, Kusters JG, Gaastra W. Nucleotide sequences of two fimbrial major subunit genes, pmpA and ucaA, from canine-uropathogenic Proteus mirabilis strains. MICROBIOLOGY (READING, ENGLAND) 1995; 141 ( Pt 6):1349-1357. [PMID: 7670636 DOI: 10.1099/13500872-141-6-1349] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Proteus mirabilis strains were isolated from dogs with urinary tract infection (UTI) and fimbriae were prepared from two strains. The N-terminal amino acid sequences of the major fimbrial subunits were determined and both sequences appeared identical to the N-terminal amino acid sequence of a urinary cell adhesin (UCA) (Wray, S. K., Hull, S. I., Cook, R. G., Barrish, J. & Hull, R. A., 1986, Infect Immun 54, 43-49). The genes of two different major fimbrial subunits were cloned using oligonucleotide probes that were designed on the basis of the N-terminal UCA sequence. Nucleotide sequencing revealed the complete ucaA gene of 540 bp (from strain IVB247) encoding a polypeptide of 180 amino acids, including a 22 amino acid signal sequence peptide, and the pmpA (P. mirabilis P-like pili) gene of 549 bp (from strain IVB219) encoding a polypeptide of 183 amino acids, including a 23 amino acid signal sequence. Hybridization experiments gave clear indications of the presence of both kinds of fimbriae in many UTI-related canine P. mirabilis isolates. However, the presence of these fimbriae could not be demonstrated in P. vulgaris or other Proteus-related species. Database analysis of amino acid sequences of major subunit proteins revealed that the UcaA protein shares about 56% amino acid identity with the F17A and F111A major fimbrial subunits from bovine enterotoxigenic Escherichia coli. In turn, the PmpA protein more closely resembled the pyelonephritis-associated pili (Pap)-like major subunit protein from UTI-related E. coli. The evolutionary relationship of UcaA, PmpA and various other fimbrial subunit proteins is presented in a phylogenetic tree.
Collapse
Affiliation(s)
- Isaac G W Bijlsma
- Department of Bacteriology, Institute of Infectious Diseases and Immunology, Faculty of Veterinary Medicine, University of Utrecht, Yalelaan 1, PO Box 80. 165, 3508 TD Utrecht, The Netherlands
| | - Linda van Dijk
- Department of Bacteriology, Institute of Infectious Diseases and Immunology, Faculty of Veterinary Medicine, University of Utrecht, Yalelaan 1, PO Box 80. 165, 3508 TD Utrecht, The Netherlands
| | - Johannes G Kusters
- Department of Bacteriology, Institute of Infectious Diseases and Immunology, Faculty of Veterinary Medicine, University of Utrecht, Yalelaan 1, PO Box 80. 165, 3508 TD Utrecht, The Netherlands
| | - Wim Gaastra
- Department of Bacteriology, Institute of Infectious Diseases and Immunology, Faculty of Veterinary Medicine, University of Utrecht, Yalelaan 1, PO Box 80. 165, 3508 TD Utrecht, The Netherlands
| |
Collapse
|
35
|
Cook SW, Mody N, Valle J, Hull R. Molecular cloning of Proteus mirabilis uroepithelial cell adherence (uca) genes. Infect Immun 1995; 63:2082-6. [PMID: 7729924 PMCID: PMC173269 DOI: 10.1128/iai.63.5.2082-2086.1995] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Proteus mirabilis bacteria are a common cause of hospital-acquired urinary tract infection. In a previous study, we described a P. mirabilis fimbrial protein, UCA, that adhered to human uroepithelial cells. Genes sufficient for expression of UCA adherence were cloned into Escherichia coli K-12. E. coli bacteria that contained the uca recombinant plasmid adhered to human uroepithelial cells. In addition, the ucaA gene encoding the structural component of UCA pili was subcloned, and its DNA sequence was determined. Amino acid sequence homology (30 to 50%) was found between mature UcaA protein and pilins from pathogenic bacteria representing several genera, including E. coli F17, G, and type 1C pilins, Haemophilus M43 pilin, and a Bordetella pilin.
Collapse
Affiliation(s)
- S W Cook
- Department of Biology, Houston Baptist University, Texas 77074, USA
| | | | | | | |
Collapse
|
36
|
Abstract
Proteus mirabilis, commonly associated with urinary tract infection, pyelonephritis and bacteremia, produces a number of fimbriae, including PMF (P. mirabilis fimbriae). Genes encoding PMF were isolated and the complete nucleotide (nt) sequence was determined. The pmf gene cluster, encoded by 5655 bp, predicts five polypeptides: PmfA (18,921 Da), PmfC (93,107 Da), PmfD (28,208 Da), PmfE (38,875 Da) and PmfF (19,661 Da). PmfA, PmfC, PmfD and PmfF share > 25% amino acid (aa) sequence identity with gene products of the pap, mrp and sfa fimbrial gene clusters. PmfE shares no similarity with any polypeptide in the SwissProt database. No regulatory gene(s) or regulatory elements were evident in the sequence. The pmf cluster shares common features with other enteric fimbrial gene clusters, but also displays features that are unique.
Collapse
Affiliation(s)
- G Massad
- Department of Medicine, University of Maryland School of Medicine, Baltimore 21201
| | | |
Collapse
|
37
|
Bahrani FK, Mobley HL. Proteus mirabilis MR/P fimbrial operon: genetic organization, nucleotide sequence, and conditions for expression. J Bacteriol 1994; 176:3412-9. [PMID: 7910820 PMCID: PMC205519 DOI: 10.1128/jb.176.11.3412-3419.1994] [Citation(s) in RCA: 57] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
Proteus mirabilis, an agent of urinary tract infection, expresses at least four fimbrial types. Among these are the MR/P (mannose-resistant/Proteus-like) fimbriae. MrpA, the structural subunit, is optimally expressed at 37 degrees C in Luria broth cultured statically for 48 h by each of seven strains examined. Genes encoding this fimbria were isolated, and the complete nucleotide sequence was determined. The mrp gene cluster encoded by 7,293 bp predicts eight polypeptides: MrpI (22,133 Da), MrpA (17,909 Da), MrpB (19,632 Da), MrpC (96,823 Da), MrpD (27,886 Da), MrpE (19,470 Da), MrpF (17,363 Da), and MrpG (13,169 Da). mrpI is upstream of the gene encoding the major structural subunit gene mrpA and is transcribed in the direction opposite to that of the rest of the operon. All predicted polypeptides share > or = 25% amino acid identity with at least one other enteric fimbrial gene product encoded by the pap, fim, smf, fan, or mrk gene clusters.
Collapse
Affiliation(s)
- F K Bahrani
- Department of Medicine, University of Maryland School of Medicine, Baltimore 21201
| | | |
Collapse
|
38
|
Kuehn MJ, Jacob-Dubuisson F, Dodson K, Slonim L, Striker R, Hultgren SJ. Genetic, biochemical, and structural studies of biogenesis of adhesive pili in bacteria. Methods Enzymol 1994; 236:282-306. [PMID: 7968616 DOI: 10.1016/0076-6879(94)36022-7] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
MESH Headings
- Adhesins, Bacterial/chemistry
- Adhesins, Bacterial/genetics
- Adhesins, Bacterial/physiology
- Amino Acid Sequence
- Bacterial Adhesion/genetics
- Bacterial Adhesion/physiology
- Bacterial Outer Membrane Proteins/chemistry
- Bacterial Outer Membrane Proteins/genetics
- Carbohydrate Sequence
- Centrifugation, Density Gradient/methods
- Conserved Sequence
- Electrophoresis, Polyacrylamide Gel/methods
- Escherichia coli/genetics
- Escherichia coli/isolation & purification
- Escherichia coli/pathogenicity
- Escherichia coli Infections/microbiology
- Fimbriae Proteins
- Fimbriae, Bacterial/physiology
- Fimbriae, Bacterial/ultrastructure
- Genes, Bacterial
- Hemagglutination Tests/methods
- Humans
- Microscopy, Electron/methods
- Models, Molecular
- Molecular Chaperones/isolation & purification
- Molecular Chaperones/physiology
- Molecular Sequence Data
- Multigene Family
- Operon
- Point Mutation
- Protein Folding
- Protein Structure, Secondary
- Urinary Tract Infections/microbiology
Collapse
Affiliation(s)
- M J Kuehn
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, Missouri 63110
| | | | | | | | | | | |
Collapse
|
39
|
Steidler L, Remaut E, Fiers W. Pap pili as a vector system for surface exposition of an immunoglobulin G-binding domain of protein A of Staphylococcus aureus in Escherichia coli. J Bacteriol 1993; 175:7639-43. [PMID: 7902348 PMCID: PMC206920 DOI: 10.1128/jb.175.23.7639-7643.1993] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
Fusion genes between papA, the gene coding for the major Pap pilus subunit, and fragments coding for an immunoglobulin G-binding domain of the Staphylococcus aureus protein A were constructed in such a way that the spa fragments were inserted following either codon 7 or 68 of the coding sequence for the mature portion of PapA. Peptides in the area of amino acids 7 and 68 of PapA are localized at the external side of the pilus. A set of pL expression plasmids containing papA and derivatives suitable for insertion were constructed. A papA gene carrying a spa insert following codon 68 was cloned back into the pap operon. The presence of this altered operon in a bacterial strain allowed the detection of immunoglobulin G-binding activity at the surfaces of the bacterial cells.
Collapse
Affiliation(s)
- L Steidler
- Laboratory of Molecular Biology, Gent University, Belgium
| | | | | |
Collapse
|
40
|
Mobley HL, Jarvis KG, Elwood JP, Whittle DI, Lockatell CV, Russell RG, Johnson DE, Donnenberg MS, Warren JW. Isogenic P-fimbrial deletion mutants of pyelonephritogenic Escherichia coli: the role of alpha Gal(1-4) beta Gal binding in virulence of a wild-type strain. Mol Microbiol 1993; 10:143-55. [PMID: 7968511 DOI: 10.1111/j.1365-2958.1993.tb00911.x] [Citation(s) in RCA: 138] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Escherichia coli strains causing acute pyelonephritis often express multiple fimbrial types and haemolysin, which may contribute to their ability to adhere to, and interact with, kidney epithelial cells. Strain CFT073, a pap+, sfa+, pil+, hly+ pyelonephritis strain, previously established as virulent in the CBA mouse model of ascending urinary tract infection and cytotoxic for cultured human renal epithelial cells, was selected for construction of isogenic strains. From a gene bank of this strain, two distinct copies of the pap operon were isolated. The two P-fimbrial determinants were subcloned into pCVD442, a positive selection suicide vector containing the sacB gene of Bacillus subtilis. Deletion mutations were introduced into each of the two constructs, within papEFG of one operon and papDEFG of the other. Suicide vectors carrying pap deletions were mobilized from E. coli SM10 lambda pir into CFT073 (NalR) and cointegrates were passaged on non-selective medium. The first pap mutation was identified by screening a Southern blot of DNA from sucrose-resistant colonies using a papEFG probe. This mutant retained the MRHA+ phenotype since a second functional copy of pap was still present. A double pap-deletion mutant, UPEC76, confirmed by Southern blotting, was unable to agglutinate human type O erythrocytes or alpha Gal(1-4)beta Gal-coated latex beads. CBA mice (N = 100) were challenged transurethrally with 10(5), 10(6), 10(7), or 10(9) cfu of strains CFT073 or UPEC76. After one week, quantitative cultures of urine, bladder, and kidney were done and histologic changes were examined. No substantive differences in organism concentration or histological findings between parent and mutant were detected in urine, bladder, or kidney at any challenge concentration. We conclude that adherence by P fimbriae of uropathogenic E. coli strain CFT073 plays only a subtle role in the development of acute pyelonephritis in the CBA mouse model.
Collapse
Affiliation(s)
- H L Mobley
- Department of Medicine, University of Maryland School of Medicine, Baltimore 21201
| | | | | | | | | | | | | | | | | |
Collapse
|
41
|
Friedrich MJ, Kinsey NE, Vila J, Kadner RJ. Nucleotide sequence of a 13.9 kb segment of the 90 kb virulence plasmid of Salmonella typhimurium: the presence of fimbrial biosynthetic genes. Mol Microbiol 1993; 8:543-58. [PMID: 8100983 DOI: 10.1111/j.1365-2958.1993.tb01599.x] [Citation(s) in RCA: 105] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The 90kb plasmid resident in Salmonella typhimurium confers increased virulence in mice by promoting the spread of infection after invasion of the intestinal epithelium. The nucleotide sequence of a 13.9kb segment of this plasmid known to encode an outer membrane protein related in sequence to components of fimbrial biosynthesis in enteric bacteria was determined. This cloned segment between the repB and repC replicon regions programmed expression of abundant surface fimbriae in Escherichia coli and S. typhimurium cells. A 7kb region contained seven open reading frames, the protein products of five of which were related in sequence to regulatory, structural, and assembly proteins of adherence fimbriae/pili, such as the P and K88 pili. These five genes and two adjacent ones which were not markedly related to proteins in the data bases comprise the pef (plasmid-encoded fimbriae) locus. Transposon TnphoA insertions in four genes in the pef locus (pefA, pefC, orf5 and orf6) resulted in active PhoA fusions and blocked or reduced the surface presentation of fimbriae, indicating that the proteins encoded by these four genes are translocated at least across the cytoplasmic membrane and contribute to formation of the fimbrial structure. The differences in genetic organization and protein sequence relatedness from other fimbrial gene clusters suggest that the pef locus might encode a novel type of fimbria. Between the pef and the repB loci, there were five open reading frames, one of which (orf8) gave rise to active PhoA fusions but was not necessary for fimbrial expression. Two of the other proteins were homologous to transcription regulatory proteins and a third was the rck gene, which encodes an outer membrane protein that confers complement resistance to serum-sensitive hosts.
Collapse
Affiliation(s)
- M J Friedrich
- Department of Microbiology, School of Medicine, University of Virginia, Charlottesville 22908
| | | | | | | |
Collapse
|
42
|
Dodson KW, Jacob-Dubuisson F, Striker RT, Hultgren SJ. Outer-membrane PapC molecular usher discriminately recognizes periplasmic chaperone-pilus subunit complexes. Proc Natl Acad Sci U S A 1993; 90:3670-4. [PMID: 8097321 PMCID: PMC46363 DOI: 10.1073/pnas.90.8.3670] [Citation(s) in RCA: 173] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
P pili are highly ordered composite structures consisting of thin fibrillar tips joined end-to-end to rigid helical rods. The production of these virulence-associated structures requires a periplasmic chaperone (PapD) and an outer membrane protein (PapC) that is the prototype member of a newly recognized class of proteins that we have named "molecular ushers." Two in vitro assays showed that the preassembly complexes that PapD forms with the three most distal tip fibrillar proteins (PapG, PapF, and PapE) bound to PapC. The relative affinity of each complex for PapC was found to correlate with the final position of the subunit type in the tip fibrillum. In contrast, the complexes PapD forms with the major component of the pilus rod, PapA, or the pilus rod initiating protein, PapK, did not recognize PapC. The in vitro data argue that differential targeting of chaperone-subunit complexes to PapC may be part of a mechanism to ensure the correctly ordered assembly of adhesive composite pili.
Collapse
Affiliation(s)
- K W Dodson
- Washington University Medical School, Department of Molecular Microbiology, St. Louis, MO 63110
| | | | | | | |
Collapse
|
43
|
Bertin Y, Girardeau JP, Der Vartanian M, Martin C. The ClpE protein involved in biogenesis of the CS31A capsule-like antigen is a member of a periplasmic chaperone family in Gram-negative bacteria. FEMS Microbiol Lett 1993. [DOI: 10.1111/j.1574-6968.1993.tb06074.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022] Open
|
44
|
Evans DG, Karjalainen TK, Evans DJ, Graham DY, Lee CH. Cloning, nucleotide sequence, and expression of a gene encoding an adhesin subunit protein of Helicobacter pylori. J Bacteriol 1993; 175:674-83. [PMID: 7678592 PMCID: PMC196205 DOI: 10.1128/jb.175.3.674-683.1993] [Citation(s) in RCA: 172] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Gene hpaA, which codes for the receptor-binding subunit of the N-acetylneuraminyllactose-binding fibrillar hemagglutinin (NLBH) of Helicobacter pylori, was cloned and sequenced. The protein expressed by hpaA, designated HpaA, was identified as the adhesin subunit on the basis of its fetuin-binding activity and its reactivity with a polyclonal, monospecific rabbit serum prepared against NLBH purified from H. pylori. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis and Western blots (immunoblots) showed that the cloned adhesin has the same molecular weight (20,000) as that found on H. pylori. Also, HpaA contains a short sequence of amino acids (KRTIQK) which are all either identical or functionally similar to those which compose the sialic acid-binding motif of Escherichia coli SfaS, K99, and CFA/I. Affinity-purified antibody specific for a 12-residue synthetic peptide that included this sequence blocked the hemagglutinating activity of H. pylori and was shown by immuno-gold electron microscopy to react with almost transparent material on unstained H. pylori cells, which is consistent with previous observations concerning the location and morphology of the NLBH.
Collapse
Affiliation(s)
- D G Evans
- Department of Medicine, Baylor College of Medicine, Houston, Texas 77030
| | | | | | | | | |
Collapse
|
45
|
Bahrani FK, Mobley HL. Proteus mirabilis MR/P fimbriae: molecular cloning, expression, and nucleotide sequence of the major fimbrial subunit gene. J Bacteriol 1993; 175:457-64. [PMID: 8093447 PMCID: PMC196160 DOI: 10.1128/jb.175.2.457-464.1993] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Proteus mirabilis, a cause of serious urinary tract infection and acute pyelonephritis, produces several putative virulence determinants, among them, fimbriae. Principally, two fimbrial types are produced by this species: mannose-resistant/Proteus-like (MR/P) fimbriae and mannose-resistant/Klebsiella-like (MR/K) fimbriae. To isolate MR/P fimbrial gene sequences, a P. mirabilis cosmid library was screened by immunoblotting and by hybridization with an oligonucleotide probe based on the N-terminal amino acid sequence of the isolated fimbrial polypeptide, ADQGHGTVKFVGSIIDAPCS. One clone, pMRP101, reacted strongly with a monoclonal antibody specific for MR/P fimbriae and with the DNA probe. This clone hemagglutinated both tannic acid-treated and untreated chicken erythrocytes with or without 50 mM D-mannose and was shown to be fimbriated by transmission electron microscopy. A 525-bp open reading frame, designated mrpA, predicted a 175-amino-acid polypeptide including a 23-amino-acid hydrophobic leader peptide. The unprocessed and processed polypeptides are predicted to be 17,909 and 15,689 Da, respectively. The N-terminal amino acid sequence of the processed fimbrial subunit exactly matched amino acid residues 24 to 43 predicted by the mrpA nucleotide sequence. The MrpA polypeptide shares 57% amino acid sequence identity with SmfA, the major fimbrial subunit of Serratia marcescens mannose-resistant fimbriae.
Collapse
Affiliation(s)
- F K Bahrani
- Division of Infectious Diseases, University of Maryland School of Medicine, Baltimore 21201
| | | |
Collapse
|
46
|
Hultgren SJ, Jacob-Dubuisson F, Jones CH, Bränden CI. PapD and superfamily of periplasmic immunoglobulin-like pilus chaperones. ADVANCES IN PROTEIN CHEMISTRY 1993; 44:99-123. [PMID: 8100380 DOI: 10.1016/s0065-3233(08)60565-3] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The formation of a P pilus requires a molecular chaperone in the periplasm and a molecular usher in the outer membrane. Each pilus is composed of six different types of proteins that are assembled into a composite fiber in a defined order. The correct folding of subunits into domains that can serve as assembly modules requires an association with the periplasmic chaperone. PapD is the prototype member of the family of bacterial pilus chaperones that have a three-dimensional structure consistent with an immunoglobulin fold. In general, proteins with an immunoglobulin fold structure have molecular recognition functions in eukaryotic cells that are often integrated with effector functions. PapD has also a recognition function, binding nascently translocated pilus subunits and maintaining them in assembly-competent conformations. The association of the chaperone with the subunit triggers the targeting of the latter to an outer membrane usher. The usher serves as a molecular gatekeeper, allowing the ordered incorporation of the pilus subunits into the pilus structure from the periplasmic chaperone complexes. The two immunoglobulin-like domains of PapD are oriented to form a cleft that contains the subunit binding site. This is a different binding paradigm from that used by either antibodies or the growth hormone receptor. The blend of genetics, biochemistry, X-ray crystallography, and carbohydrate chemistry in the study of pili biogenesis will continue to give insight into some of the most basic intellectual challenges in molecular biology concerning how proteins fold into domains that serve as modules for the formation of larger assemblies, and relating these processes to microbial pathogenesis.
Collapse
Affiliation(s)
- S J Hultgren
- Department of Molecular Biology, Washington University Medical School, St. Louis, Missouri 63110
| | | | | | | |
Collapse
|
47
|
Abstract
The structure of the P pili from Escherichia coli has been studied using X-ray fiber diffraction and scanning transmission electron microscopy (STEM). Analysis of the fiber diffraction data indicates that the pili are constituted largely of structural subunits arranged helically with approximately 33 subunits in 10 turns in an axial repeat of 244.5 +/- 1.8 A. Radial electron density distributions calculated from equatorial diffraction data and STEM data indicate that the pili are about 65 A in diameter with a small central cavity roughly 15 A across. The principal protein component of the pili is PapA, which has a molecular weight of 16.5 kDa. Assuming that each subunit consists of a single PapA molecule, the mass-per-unit-length of the pili predicted from the X-ray data is 2.23 kDa/A. Measurements of mass-per-unit-length were also made through the analysis of STEM images. These measurements indicate a value of 2.13 +/- 0.14 kDa/A. STEM images demonstrated the presence of thin, thread-like structures emerging from the ends of pili and spanning breaks in the pili structure. These structures, which have been observed under other conditions, have been termed fibrillae. In the STEM images the fibrillae appear about 20 A in diameter. The mass-per-unit-length of the fibrillae was estimated using the STEM data to be 0.4 kDa/A. These data are consistent with the fibrillae representing an unwound or unraveled form of the pili proteins overstretched to about five times the length they would have in the intact pili.
Collapse
Affiliation(s)
- M Gong
- Department of Physics, Boston University, MA 02215
| | | |
Collapse
|
48
|
Sheng YJ, Otsuki K, Sanekata T, Tsubokura M, Koga T, Tsuji H, Oka T, Takumi K. Characterization of an amorphous and soluble hemagglutinin from Yersinia pseudotuberculosis. Microbiol Immunol 1992; 36:1129-43. [PMID: 1491617 DOI: 10.1111/j.1348-0421.1992.tb02117.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Yersinia pseudotuberculosis which were screened out depending on auto-agglutination and Ca2+ dependency, were examined for their production of hemagglutinin (HA), and its purification and characterization were performed. The HA with a broad reactivity with various mammalian erythrocytes was recovered from the culture supernatant of these strains grown at 37 C but not 25 C. HAs from two strains, R148R and T1040, were purified by salt precipitation, gel filtration and anion-exchange chromatography by HPLC. Both purified HAs were cysteine-deficient acidic protein with an apparent molecular weight in the range of 15,000 to 16,000. N-terminal amino acid sequences of the first 25 residues were found to share 12% identity with that of afimbrial adhesin from enterotoxigenic Escherichia coli 2230. Immunoelectron microscopy and immunodiffusion test with polyclonal antiserum raised against the purified R148RHA demonstrated that the HA was associated with the amorphous aggregates which were detached from bacteria. These results suggest that the HA of Y. pseudotuberculosis belongs to a third type of HA produced by the yersinial species.
Collapse
Affiliation(s)
- Y J Sheng
- Department of Veterinary Microbiology, Faculty of Agriculture, University of Tottori, Japan
| | | | | | | | | | | | | | | |
Collapse
|
49
|
Marklund BI, Tennent JM, Garcia E, Hamers A, Båga M, Lindberg F, Gaastra W, Normark S. Horizontal gene transfer of the Escherichia coli pap and prs pili operons as a mechanism for the development of tissue-specific adhesive properties. Mol Microbiol 1992; 6:2225-42. [PMID: 1357526 DOI: 10.1111/j.1365-2958.1992.tb01399.x] [Citation(s) in RCA: 160] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Escherichia coli strains bind to Gal alpha 1-4Gal-containing glycolipids via P pili-associated G-adhesins. Three functional classes of adhesins with different binding specificities are encoded by conserved G-alleles. We suggest that the Class I papG-allele of strain J96 is a novel acquisition possibly introduced via horizontal gene transfer into one of the two P pili gene clusters carried by this strain. Closely related strains in the ECOR collection of natural E. coli isolates carry either a Class II or a Class III G-adhesin. Data indicate that genetic exchanges involving either entire pap or prs gene clusters or individual pap/prs genes have occurred. We propose that the retention and spread of pap/prs DNA among E. coli is the result of selection pressure exerted by mammalian intestinal isoreceptors.
Collapse
Affiliation(s)
- B I Marklund
- Department of Microbiology, University of Umeå, Sweden
| | | | | | | | | | | | | | | |
Collapse
|
50
|
Ho AS, Sohel I, Schoolnik GK. Cloning and characterization of fxp, the flexible pilin gene of Aeromonas hydrophila. Mol Microbiol 1992; 6:2725-32. [PMID: 1360140 DOI: 10.1111/j.1365-2958.1992.tb01449.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The flexible pilus of Aeromonas hydrophila is a morphologically and biochemically unique organelle which binds eukaryotic cell surfaces and whose expression is induced by specific physiochemical conditions. fxp, the structural gene coding for the flexible pilus subunit, was localized on a 7.6kb plasmid of A. hydrophila strain AH26. A putative Shine-Dalgarno sequence and -10 and -35 regions were identified, a signal peptide sequence delineated, and the coding sequence compared with other bacterial sequences and found to be unique. Plasmid and chromosomal DNA was prepared from 66 other Aeromonas strains and 12 strains from other bacterial genera and examined by Southern blot hybridization using a labelled fxp oligonucleotide and the 7.6kb plasmid as probes. No hybridizing sequences were identified except in the original strain, AH26. It is proposed that fxp codes for a highly evolved organelle, possibly widely distributed in nature, but that it is carried on a genetic element that is rapidly lost from most strains upon in vitro cultivation and storage.
Collapse
Affiliation(s)
- A S Ho
- Department of Microbiology and Immunology, Stanford University, California 94305
| | | | | |
Collapse
|