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Jeckelmann JM, Erni B. The mannose phosphotransferase system (Man-PTS) - Mannose transporter and receptor for bacteriocins and bacteriophages. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2020; 1862:183412. [PMID: 32710850 DOI: 10.1016/j.bbamem.2020.183412] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/28/2020] [Revised: 07/08/2020] [Accepted: 07/14/2020] [Indexed: 02/06/2023]
Abstract
Mannose transporters constitute a superfamily (Man-PTS) of the Phosphoenolpyruvate Carbohydrate Phosphotransferase System (PTS). The membrane complexes are homotrimers of protomers consisting of two subunits, IIC and IID. The two subunits without recognizable sequence similarity assume the same fold, and in the protomer are structurally related by a two fold pseudosymmetry axis parallel to membrane-plane (Liu et al. (2019) Cell Research 29 680). Two reentrant loops and two transmembrane helices of each subunit together form the N-terminal transport domain. Two three-helix bundles, one of each subunit, form the scaffold domain. The protomer is stabilized by a helix swap between these bundles. The two C-terminal helices of IIC mediate the interprotomer contacts. PTS occur in bacteria and archaea but not in eukaryotes. Man-PTS are abundant in Gram-positive bacteria living on carbohydrate rich mucosal surfaces. A subgroup of IICIID complexes serve as receptors for class IIa bacteriocins and as channel for the penetration of bacteriophage lambda DNA across the inner membrane. Some Man-PTS are associated with host-pathogen and -symbiont processes.
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Affiliation(s)
- Jean-Marc Jeckelmann
- Institute of Biochemistry and Molecular Medicine, University of Bern, Bern, Switzerland.
| | - Bernhard Erni
- Department of Chemistry and Biochemistry, University of Bern, Bern, Switzerland.
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2
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Jeckelmann JM, Erni B. Carbohydrate Transport by Group Translocation: The Bacterial Phosphoenolpyruvate: Sugar Phosphotransferase System. Subcell Biochem 2019; 92:223-274. [PMID: 31214989 DOI: 10.1007/978-3-030-18768-2_8] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
The Bacterial Phosphoenolpyruvate (PEP) : Sugar Phosphotransferase System (PTS) mediates the uptake and phosphorylation of carbohydrates, and controls the carbon- and nitrogen metabolism in response to the availability of sugars. PTS occur in eubacteria and in a few archaebacteria but not in animals and plants. All PTS comprise two cytoplasmic phosphotransferase proteins (EI and HPr) and a species-dependent, variable number of sugar-specific enzyme II complexes (IIA, IIB, IIC, IID). EI and HPr transfer phosphorylgroups from PEP to the IIA units. Cytoplasmic IIA and IIB units sequentially transfer phosphates to the sugar, which is transported by the IIC and IICIID integral membrane protein complexes. Phosphorylation by IIB and translocation by IIC(IID) are tightly coupled. The IIC(IID) sugar transporters of the PTS are in the focus of this review. There are four structurally different PTS transporter superfamilies (glucose, glucitol, ascorbate, mannose) . Crystal structures are available for transporters of two superfamilies: bcIICmal (MalT, 5IWS, 6BVG) and bcIICchb (ChbC, 3QNQ) of B. subtilis from the glucose family, and IICasc (UlaA, 4RP9, 5ZOV) of E. coli from the ascorbate superfamily . They are homodimers and each protomer has an independent transport pathway which functions by an elevator-type alternating-access mechanism. bcIICmal and bcIICchb have the same fold, IICasc has a completely different fold. Biochemical and biophysical data accumulated in the past with the transporters for mannitol (IICBAmtl) and glucose (IICBglc) are reviewed and discussed in the context of the bcIICmal crystal structures. The transporters of the mannose superfamily are dimers of protomers consisting of a IIC and a IID protein chain. The crystal structure is not known and the topology difficult to predict. Biochemical data indicate that the IICIID complex employs a different transport mechanism . Species specific IICIID serve as a gateway for the penetration of bacteriophage lambda DNA across, and insertion of class IIa bacteriocins into the inner membrane. PTS transporters are inserted into the membrane by SecYEG translocon and have specific lipid requirements. Immunoelectron- and fluorescence microscopy indicate a non-random distribution and supramolecular complexes of PTS proteins.
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Affiliation(s)
- Jean-Marc Jeckelmann
- Institute of Biochemistry and Molecular Medicine, University of Bern, Bühlstrasse 28, 3012, Bern, Switzerland.
| | - Bernhard Erni
- Institute of Biochemistry and Molecular Medicine, University of Bern, Bühlstrasse 28, 3012, Bern, Switzerland
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3
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Lee AJ, Clark RW, Youn H, Ponter S, Burstyn JN. Guanidine hydrochloride-induced unfolding of the three heme coordination states of the CO-sensing transcription factor, CooA. Biochemistry 2009; 48:6585-97. [PMID: 19594171 DOI: 10.1021/bi801827j] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
CooA is a heme-dependent CO-sensing transcription factor that has three observable heme coordination states. There is some evidence that each CooA heme state has a distinct protein conformation; the goal of this study was to characterize these conformations by measuring their structural stabilities through guanidine hydrochloride (GuHCl) denaturation. By studying the denaturation processes of the Fe(III) state of WT CooA and several variants, we were able to characterize independent unfolding processes for each domain of CooA. This information was used to compare the unfolding profiles of various CooA heme activation states [Fe(III), Fe(II), and Fe(II)-CO] to show that the heme coordination state changes the stability of the effector binding domain. A mechanism consistent with the data predicts that all CooA coordination states and variants undergo unfolding of the DNA-binding domain between 2 and 3 M GuHCl with a free energy of unfolding of approximately 17 kJ/mol, while unfolding of the heme domain is variable and dependent on the heme coordination state. The findings support a model in which changes in heme ligation alter the structural stability of the heme domain and dimer interface but do not alter the stability of the DNA-binding domain. These studies provide evidence that the domains of transcription factors are modular and that allosteric signaling occurs through changes in the relative positions of the protein domains without affecting the structure of the DNA-binding region.
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Affiliation(s)
- Andrea J Lee
- Department of Chemistry, University of Wisconsin, Madison, Wisconsin 53706, USA
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Hu J, Hu K, Williams DC, Komlosh ME, Cai M, Clore GM. Solution NMR structures of productive and non-productive complexes between the A and B domains of the cytoplasmic subunit of the mannose transporter of the Escherichia coli phosphotransferase system. J Biol Chem 2008; 283:11024-37. [PMID: 18270202 PMCID: PMC2447639 DOI: 10.1074/jbc.m800312200] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2008] [Indexed: 11/06/2022] Open
Abstract
Solution structures of complexes between the isolated A (IIA(Man)) and B (IIB(Man)) domains of the cytoplasmic component of the mannose transporter of Escherichia coli have been solved by NMR. The complex of wild-type IIA(Man) and IIB(Man) is a mixture of two species comprising a productive, phosphoryl transfer competent complex and a non-productive complex with the two active site histidines, His-10 of IIA(Man) and His-175 of IIB(Man), separated by approximately 25A. Mutation of the active site histidine, His-10, of IIA(Man) to a glutamate, to mimic phosphorylation, results in the formation of a single productive complex. The apparent equilibrium dissociation constants for the binding of both wild-type and H10E IIA(Man) to IIB(Man) are approximately the same (K(D) approximately 0.5 mM). The productive complex can readily accommodate a transition state involving a pentacoordinate phosphoryl group with trigonal bipyramidal geometry bonded to the Nepsilon2 atom of His-10 of IIA(Man) and the Ndelta1 atom of His-175 of IIB(Man) with negligible (<0.2A) local backbone conformational changes in the immediate vicinity of the active site. The non-productive complex is related to the productive one by a approximately 90 degrees rotation and approximately 37A translation of IIB(Man) relative to IIA(Man), leaving the active site His-175 of IIB(Man) fully exposed to solvent in the non-productive complex. The interaction surface on IIA(Man) for the non-productive complex comprises a subset of residues used in the productive complex and in both cases involves both subunits of IIA(Man). The selection of the productive complex by IIA(Man)(H10E) can be attributed to neutralization of the positively charged Arg-172 of IIB(Man) at the center of the interface. The non-productive IIA(Man)-IIB(Man) complex may possibly be relevant to subsequent phosphoryl transfer from His-175 of IIB(Man) to the incoming sugar located on the transmembrane IIC(Man)-IID(Man) complex.
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Affiliation(s)
- Jun Hu
- Laboratory of Chemical Physics, NIDDK, National Institutes of Health, Bethesda, Maryland 20892, USA
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Sapranauskas R, Lubys A. Random gene dissection: a tool for the investigation of protein structural organization. Biotechniques 2005; 39:395-402. [PMID: 16206911 DOI: 10.2144/05393rr01] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
To investigate the domain structure of proteins and the function of individual domains, proteins are usually subjected to limited proteolysis, followed by isolation of protein fragments and determination of their functions. We have developed an approach we call random gene dissection (RGD) for the identification of functional protein domains and their interdomain regions as well as their in vivo complementing fragments. The approach was tested on a two-domain protein, the type IIS restriction endonuclease BfiI. The collection of BfiI insertional mutants was screened for those that are endonucleolytically active and thus induce the SOS DNA repair response. Sixteen isolated mutants of the wild-type specificity contained insertions that were dispersed in a relatively large region of the target recognition domain. They split the gene into two complementing parts that separately were unable to induce the SOS DNA repair response. In contrast, all 19 mutants of relaxed specificity contained the cassette inserted into a very narrow interdomain region that connects BfiI domains responsible for DNA recognition and for cleavage. As expected, only the N-terminal fragment of BfiI was required to induce SOS response. Our results demonstrate that RGD can be used as a general method to identify complementing fragments and functional domains in enzymes.
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Vreuls C, Filée P, Van Melckebeke H, Aerts T, De Deyn P, Llabrès G, Matagne A, Simorre JP, Frère JM, Joris B. Guanidinium chloride denaturation of the dimeric Bacillus licheniformis BlaI repressor highlights an independent domain unfolding pathway. Biochem J 2005; 384:179-90. [PMID: 15285720 PMCID: PMC1134101 DOI: 10.1042/bj20040658] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The Bacillus licheniformis 749/I BlaI repressor is a prokaryotic regulator that, in the absence of a beta-lactam antibiotic, prevents the transcription of the blaP gene, which encodes the BlaP beta-lactamase. The BlaI repressor is composed of two structural domains. The 82-residue NTD (N-terminal domain) is a DNA-binding domain, and the CTD (C-terminal domain) containing the next 46 residues is a dimerization domain. Recent studies have shown the existence of the monomeric, dimeric and tetrameric forms of BlaI in solution. In the present study, we analyse the equilibrium unfolding of BlaI in the presence of GdmCl (guanidinium chloride) using different techniques: intrinsic and ANS (8-anilinonaphthalene-l-sulphonic acid) fluorescence, far- and near-UV CD spectroscopy, cross-linking, analytical ultracentrifugation, size exclusion chromatography and NMR spectroscopy. In addition, the intact NTD and CTD were purified after proteolysis of BlaI by papain, and their unfolding by GdmCl was also studied. GdmCl-induced equilibrium unfolding was shown to be fully reversible for BlaI and for the two isolated fragments. The results demonstrate that the NTD and CTD of BlaI fold/unfold independently in a four-step process, with no significant co-operative interactions between them. During the first step, the unfolding of the BlaI CTD occurs, followed in the second step by the formation of an 'ANS-bound' intermediate state. Cross-linking and analytical ultracentrifugation experiments suggest that the dissociation of the dimer into two partially unfolded monomers takes place in the third step. Finally, the unfolding of the BlaI NTD occurs at a GdmCl concentration of approx. 4 M. In summary, it is shown that the BlaI CTD is structured, more flexible and less stable than the NTD upon GdmCl denaturation. These results contribute to the characterization of the BlaI dimerization domain (i.e. CTD) involved in the induction process.
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Affiliation(s)
- Christelle Vreuls
- *Centre d’ingénierie des Protéines, Institut de Chimie B6a, Université de Liège, Sart-Tilman, B4000 Liège, Belgium
- †Laboratoire de Physique Biomédicale, Institut de Physique B5, Université de Liège, Sart-Tilman, B4000 Liège, Belgium
| | - Patrice Filée
- *Centre d’ingénierie des Protéines, Institut de Chimie B6a, Université de Liège, Sart-Tilman, B4000 Liège, Belgium
| | - Hélène Van Melckebeke
- ‡Institut de Biologie Structurale Jean-Pierre Ebel, CEA-CNRS-UJF, 38027 Grenoble, France
| | - Tony Aerts
- §Department of Biomedical Sciences, University of Antwerp, Groenenborgerlaan 171, B-2020 Antwerp, Belgium
| | - Peter De Deyn
- §Department of Biomedical Sciences, University of Antwerp, Groenenborgerlaan 171, B-2020 Antwerp, Belgium
| | - Gabriel Llabrès
- †Laboratoire de Physique Biomédicale, Institut de Physique B5, Université de Liège, Sart-Tilman, B4000 Liège, Belgium
| | - André Matagne
- *Centre d’ingénierie des Protéines, Institut de Chimie B6a, Université de Liège, Sart-Tilman, B4000 Liège, Belgium
| | - Jean-Pierre Simorre
- ‡Institut de Biologie Structurale Jean-Pierre Ebel, CEA-CNRS-UJF, 38027 Grenoble, France
| | - Jean-Marie Frère
- *Centre d’ingénierie des Protéines, Institut de Chimie B6a, Université de Liège, Sart-Tilman, B4000 Liège, Belgium
| | - Bernard Joris
- *Centre d’ingénierie des Protéines, Institut de Chimie B6a, Université de Liège, Sart-Tilman, B4000 Liège, Belgium
- To whom correspondence should be addressed (email )
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Williams DC, Cai M, Suh JY, Peterkofsky A, Clore GM. Solution NMR structure of the 48-kDa IIAMannose-HPr complex of the Escherichia coli mannose phosphotransferase system. J Biol Chem 2005; 280:20775-84. [PMID: 15788390 PMCID: PMC1357268 DOI: 10.1074/jbc.m501986200] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The solution structure of the 48-kDa IIA(Man)-HPr complex of the mannose branch of the Escherichia coli phosphotransferase system has been solved by NMR using conjoined rigid body/torsion angle-simulated annealing on the basis of intermolecular nuclear Overhauser enhancement data and residual dipolar couplings. IIA(Man) is dimeric and has two symmetrically related binding sites per dimer for HPr. A convex surface on HPr, formed primarily by helices 1 and 2, interacts with a deep groove at the interface of the two subunits of IIA(Man). The interaction surface on IIA(Man) is predominantly helical, comprising helix 3 from the subunit that bears the active site His-10 and helices 1, 4, and 5 from the other subunit. The total buried accessible surface area at the protein-protein interface is 1450 A(2). The binding sites on the two proteins are complementary in terms of shape and distribution of hydrophobic, hydrophilic, and charged residues. The active site histidines, His-10 of IIA(Man) and His-15 (italics indicate HPr residues) of HPr, are in close proximity. An associative transition state involving a pentacoordinate phosphoryl group with trigonal bipyramidal geometry bonded to the N-epsilon2 atom of His-10 and the N-delta1 atom of His-15 can be readily formed with negligible displacement in the backbone coordinates of the residues immediately adjacent to the active site histidines. Comparing the structures of complexes of HPr with three other structurally unrelated phosphotransferase system proteins, enzymes I, IIA(glucose), and IIA(mannitol), reveals a number of common features that provide a molecular basis for understanding how HPr specifically recognizes a wide range of diverse proteins.
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Affiliation(s)
| | - Mengli Cai
- From the Laboratory of Chemical Physics, NIDDK, and the
| | | | - Alan Peterkofsky
- Laboratory of Cell Biology, NHLBI, National Institutes of Health, Bethesda, Maryland 20892
| | - G. Marius Clore
- From the Laboratory of Chemical Physics, NIDDK, and the
- ¶ To whom correspondence should be addressed: Laboratory of Chemical Physics, Bldg. 5, Rm. B1-30I, NIDDK, NIH, Bethesda, MD 20892-0520. Tel.: 301-496-0782; Fax: 301-496-0825; E-mail:
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8
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Gutknecht R, Beutler R, Garcia-Alles LF, Baumann U, Erni B. The dihydroxyacetone kinase of Escherichia coli utilizes a phosphoprotein instead of ATP as phosphoryl donor. EMBO J 2001; 20:2480-6. [PMID: 11350937 PMCID: PMC125457 DOI: 10.1093/emboj/20.10.2480] [Citation(s) in RCA: 87] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The dihydroxyacetone kinase (DhaK) of Escherichia coli consists of three soluble protein subunits. DhaK (YcgT; 39.5 kDa) and DhaL (YcgS; 22.6 kDa) are similar to the N- and C-terminal halves of the ATP-dependent DhaK ubiquitous in bacteria, animals and plants. The homodimeric DhaM (YcgC; 51.6 kDa) consists of three domains. The N-terminal dimerization domain has the same fold as the IIA domain (PDB code 1PDO) of the mannose transporter of the bacterial phosphoenolpyruvate:sugar phosphotransferase system (PTS). The middle domain is similar to HPr and the C-terminus is similar to the N-terminal domain of enzyme I (EI) of the PTS. DhaM is phosphorylated three times by phosphoenolpyruvate in an EI- and HPr-dependent reaction. DhaK and DhaL are not phosphorylated. The IIA domain of DhaM, instead of ATP, is the phosphoryl donor to dihydroxyacetone (Dha). Unlike the carbohydrate-specific transporters of the PTS, DhaK, DhaL and DhaM have no transport activity.
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Affiliation(s)
| | | | | | | | - Bernhard Erni
- Departement für Chemie und Biochemie, Universität Bern, Freiestrasse 3, CH-3012 Bern, Switzerland
Corresponding author e-mail:
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9
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Collinet B, Herve M, Pecorari F, Minard P, Eder O, Desmadril M. Functionally accepted insertions of proteins within protein domains. J Biol Chem 2000; 275:17428-33. [PMID: 10747943 DOI: 10.1074/jbc.m000666200] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Experiments were designed to explore the tolerance of protein structure and folding to very large insertions of folded protein within a structural domain. Dihydrofolate reductase and beta-lactamase have been inserted in four different positions of phosphoglycerate kinase. The resultant chimeric proteins are all overexpressed, and the host as well as the inserted partners are functional. Although not explicitly designed, functional coupling between the two fused partners was observed in some of the chimeras. These results show that the tolerance of protein structures to very large structured insertions is more general than previously expected and supports the idea that the natural sequence continuity of a structural domain is not required for the folding process. These results directly suggest a new experimental approach to screen, for example, for folded protein in randomized polypeptide sequences.
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Affiliation(s)
- B Collinet
- Laboratoire de Modélisation et d'Ingénierie des Protéines, EP1088 Université de Paris-Sud, F-91405 Orsay Cedex, France
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10
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Wenk M, Jaenicke R. Calorimetric analysis of the Ca(2+)-binding betagamma-crystallin homolog protein S from Myxococcus xanthus: intrinsic stability and mutual stabilization of domains. J Mol Biol 1999; 293:117-24. [PMID: 10512720 DOI: 10.1006/jmbi.1999.3146] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The betagamma-crystallin superfamily consists of a class of homologous two-domain proteins with Greek-key fold. Protein S, a Ca(2+)-binding spore-coat protein from the soil bacterium Myxococcus xanthus exhibits a high degree of sequential and structural homology with gammaB-crystallin from the vertebrate eye lens. In contrast to gammaB-crystallin, which undergoes irreversible aggregation upon thermal unfolding, protein S folds reversibly and may therefore serve as a model in the investigation of the thermodynamic stability of the eye-lens crystallins. The thermal denaturation of recombinant protein S (PS) and its isolated domains was studied by differential scanning calorimetry in the absence and in the presence of Ca(2+) at varying pH. Ca(2+)-binding leads to a stabilization of PS and its domains and increases the cooperativity of their equilibrium unfolding transitions. The isolated N-terminal and C-terminal domains (NPS and CPS) obey the two-state model, independent of the pH and Ca(2+)-binding; in the case of PS, under all conditions, an equilibrium intermediate is populated. The first transition of PS may be assigned to the denaturation of the C-terminal domain and the loss of domain interactions, whereas the second one coincides with the denaturation of the isolated N-terminal domain. At pH 7.0, in the presence of Ca(2+), where PS exhibits maximal stability, the domain interactions at 20 degrees C contribute 20 kJ/mol to the overall stability of the intact protein.
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Affiliation(s)
- M Wenk
- Institut für Biophysik und Physikalische Biochemie, Universität Regensburg, Regensburg, D-93040, Germany
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11
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Robillard GT, Broos J. Structure/function studies on the bacterial carbohydrate transporters, enzymes II, of the phosphoenolpyruvate-dependent phosphotransferase system. BIOCHIMICA ET BIOPHYSICA ACTA 1999; 1422:73-104. [PMID: 10393270 DOI: 10.1016/s0304-4157(99)00002-7] [Citation(s) in RCA: 88] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Affiliation(s)
- G T Robillard
- The University of Groningen, Groningen Biomolecular Sciences and Biotechnology Institute, Nienborgh 4, 9747 AG, Groningen, The Netherlands.
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12
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Markovic-Housley Z, Stolz B, Lanz R, Erni B. Effects of tryptophan to phenylalanine substitutions on the structure, stability, and enzyme activity of the IIAB(Man) subunit of the mannose transporter of Escherichia coli. Protein Sci 1999; 8:1530-5. [PMID: 10422843 PMCID: PMC2144386 DOI: 10.1110/ps.8.7.1530] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
The hydrophilic subunit of the mannose transporter (IIAB(Man)) of Escherichia coli is a homodimer that contains four tryptophans per monomer, three in the N-terminal domain (Trp12, Trp33, and Trp69) and one in the C-terminal domain (Trp182). Single and double Trp-Phe mutants of IIABMan and of the IIA domain were produced. Fluorescence emission studies revealed that Trp33 and Trp12 are the major fluorescence emitters, Trp69 is strongly quenched in the native protein and Trp182 strongly blue shifted, indicative of a hydrophobic environment. Stabilities of the Trp mutants of dimeric IIA(Man) and IIAB(Man) were estimated from midpoints of the GdmHCl-induced unfolding transitions and from the amount of dimers that resisted dissociation by SDS (sodium dodecyl sulfate), respectively. W12F exhibited increased stability, but only 6% of the wild-type phosphotransferase activity, whereas W33F was marginally and W69F significantly destabilized, but fully active. Second site mutations W33F and W69F in the background of the W12F mutation reduced protein stability and suppressed the functional defect of W12F. These results suggest that flexibility is required for the adjustments of protein-protein contacts necessary for the phosphoryltransfer between the phosphorylcarrier protein HPr, IIA(Man), IIB(Man), and the incoming mannose bound to the transmembrane IIC(Man)-IID(Man) complex.
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Affiliation(s)
- Z Markovic-Housley
- Department of Structural Biology, Biocenter, University of Basel, Switzerland
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13
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Wenk M, Baumgartner R, Holak TA, Huber R, Jaenicke R, Mayr EM. The domains of protein S from Myxococcus xanthus: structure, stability and interactions. J Mol Biol 1999; 286:1533-45. [PMID: 10064714 DOI: 10.1006/jmbi.1999.2582] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Protein S from Myxococcus xanthus is a member of the beta gamma-crystallin superfamily. Its N and C-terminal domains (NPS and CPS, respectively) show a high degree of structural similarity and possess the capacity to bind two calcium ions per domain. For NPS, their positions were determined by X-ray diffraction at 1.8 A resolution, making use of molecular replacement with the NMR structure as search model. The overall topology of NPS is found to be practically the same as in complete protein S. In natural protein S, the domains fold independently, with a significant increase in stability and cooperativity of folding in the presence of Ca2+. The recombinant isolated domains are stable monomers which do not show any tendency to combine to "nicked" full-length protein S. In order to investigate the stability and folding of natural protein S and its isolated domains, spectroscopic techniques were applied, measuring the reversible urea and temperature-induced unfolding transitions at varying pH. The increment of Ca2+ to the free energy of stabilization amounts to -10 and -5 kJ/mol for NPS and CPS, respectively. For both NPS and CPS, in the absence and in the presence of 3 mM CaCl2, the two-state model is valid. Comparing DeltaGU-->N for CPS (-21 kJ/mol at pH 7, liganded with Ca2+) with its increment in the intact two-domain protein, the stability of the isolated domain turns out to be decreased in a pH-dependent manner. In contrast, the stability of Ca2+-loaded NPS (DeltaGU-->N=-31 kJ/mol, pH 7) is nearly unchanged down to pH 2 where Ca2+ is released (DeltaGU-->N=-26 kJ/mol, pH 2). In intact protein S, the N-terminal domain is destabilized relative to NPS. Evidently, apart from Ca2+ binding, well-defined domain interactions contribute significantly to the overall stability of intact protein S.
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Affiliation(s)
- M Wenk
- Institut für Biophysik und Physikalische Biochemie, Universität Regensburg, Regensburg, D-93040, Germany
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14
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Gutknecht R, Flükiger K, Lanz R, Erni B. Mechanism of phosphoryl transfer in the dimeric IIABMan subunit of the Escherichia coli mannose transporter. J Biol Chem 1999; 274:6091-6. [PMID: 10037691 DOI: 10.1074/jbc.274.10.6091] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The mannose transporter of bacterial phosphoenolpyruvate:sugar phosphotransferase system (PTS) mediates uptake of mannose, glucose, and related hexoses by a mechanism that couples translocation with phosphorylation of the substrate. It consists of the transmembrane IICMan.IIDMan complex and the cytoplasmic IIABMan subunit. IIABMan has two domains (IIA and IIB) that are linked by a 60-A long alanine-proline-rich linker. IIABMan transfers phosphoryl groups from the phospho-histidine-containing phospho-carrier protein of the PTS to His-10 on IIA, hence to His-175 on IIB, and finally to the 6'-OH of the transported hexose. IIABMan occurs as a stable homodimer. The subunit contact is mediated by a swap of beta-strands and an extensive contact area between the IIA domains. The H10C and H175C single and the H10C/H175C double mutants were used to characterize the phosphoryl transfer between IIA to IIB. Subunits do not exchange between dimers under physiological conditions, but slow phosphoryl transfer can take place between subunits from different dimers. Heterodimers of different subunits were produced in vitro by GuHCl-induced unfolding and refolding of mixtures of two different homodimers. With respect to wild-type homodimers, the heterodimers have the following activities: wild-type.H10C, 50%; wild-type.H175C 45%; H10C.H175C, 37%; and wild-type.H10C/H175C (double mutant), 29%. Taken together, this indicates that both cis and trans pathways contribute to the maximal phosphotransferase activity of IIABMan. A phosphoryl group on a IIA domain can be transferred either to the IIB domain on the same or on the second subunit in the dimer, and interruption of one of the two pathways results in a reduction of the activity to 70-80% of the control.
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Affiliation(s)
- R Gutknecht
- Departement für Chemie und Biochemie, Universität Bern, Freiestrasse 3, CH-3012, Bern, Switzerland
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15
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Szilágyi AN, Vas M. Sequential domain refolding of pig muscle 3-phosphoglycerate kinase: kinetic analysis of reactivation. FOLDING & DESIGN 1999; 3:565-75. [PMID: 9889168 DOI: 10.1016/s1359-0278(98)00071-6] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
BACKGROUND Slow refolding of 3-phosphoglycerate kinase is supposed to be caused mainly by its domain structure: folding of the C-terminal domain and/or domain pairing has been suggested to be the rate-limiting step. A slow isomerization has been observed during refolding of the isolated C-terminal proteolytic fragment (larger than the C-domain of about 22 kDa by 5 kDa) of the pig muscle enzyme. Here, the role of this step in the reformation of the active enzyme species is investigated. RESULTS The time course of reactivation during refolding of 3-phosphoglycerate kinase or its complementary proteolytic fragments (residues 1-155 and 156-416) exhibits a pronounced lag-phase indicating the formation of an inactive folding intermediate. The whole process, which leads to a high (60-85%) recovery of the enzyme activity, can be described by two consecutive first-order steps (with rate constants 0.012+/-0.0035 and 0.007+/-0.0020 s(-1)). A prior renaturation of the C-fragment restores MgATP binding by the C-domain and abolishes the faster step, allowing the separate observation of the slower step. In accordance with this, refolding of the C-domain as monitored by a change in Trp fluorescence occurs at a rate similar to that of the faster step. CONCLUSIONS In addition to the previously observed slow refolding step (0.012 s(-1)) within the C-domain, the occurrence of another slow step (0.007 s(-1)), probably within the N-domain, is detected. The independence of the folding of the C-domain is demonstrated whereas, from the comparative kinetic analysis, independent folding of the N-domain looks less probable. Our data are more compatible with a sequential, rather than random, mechanism and suggest that folding of the C-domain, leading to an inactive intermediate, occurs first, followed by folding of the N-domain.
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Affiliation(s)
- A N Szilágyi
- Institute of Enzymology, Biological Research Centre, Hungarian Academy of Sciences, Budapest
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Palme S, Slingsby C, Jaenicke R. Mutational analysis of hydrophobic domain interactions in gamma B-crystallin from bovine eye lens. Protein Sci 1997; 6:1529-36. [PMID: 9232654 PMCID: PMC2143740 DOI: 10.1002/pro.5560060717] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
gamma B-crystallin is a monomeric member of the beta gamma-superfamily of vertebrate eye lens proteins. It consists of two similar domains with all-beta Greek key topology associating about an approximate two-fold axis. At pH 2, with urea as the denaturant, the domains show independent equilibrium unfolding transitions, suggesting different intrinsic stabilities. Denaturation experiments using recombinant one- or two-domain proteins showed that the N-terminal domain on its own exhibits unaltered intrinsic stability but contributes significantly to the stability of its C-terminal partner. It has been suggested that docking of the domains is determined by a hydrophobic interface that includes phenylalanine at position 56 of the N-terminal domain. In order to test this hypothesis, F56 was substituted by site-directed mutagenesis in both complete gamma B-crystallin and its isolated N-terminal domain. All mutations destabilize the N-terminal domain to about the same extent but affect the C-terminal domain in a different way. Replacement by the small alanine side chain or the charged aspartic acid residue results in a significant destabilization of the C-terminal domain, whereas the more bulky tryptophan residue causes only a moderate decrease in stability. In the mutants F56A and F56D, equilibrium unfolding transitions obtained by circular dichroism and intrinsic fluorescence differ, suggesting a more complex denaturation behavior than the one observed for gamma B wild type. These results confirm how mutations in one crystallin domain can affect the stability of another when they occur at the interface. The results strongly suggest that size, hydrophobicity, and optimal packing of amino acids involved in these interactions are critical for the stability of gamma B-crystallin.
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Affiliation(s)
- S Palme
- Institut für Biophysik und Physikalische Biochemie, Universität Regensburg, Germany
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17
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Seip S, Lanz R, Gutknecht R, Flükiger K, Erni B. The fructose transporter of Bacillus subtilis encoded by the lev operon: backbone assignment and secondary structure of the IIB(Lev) subunit. EUROPEAN JOURNAL OF BIOCHEMISTRY 1997; 243:306-14. [PMID: 9030753 DOI: 10.1111/j.1432-1033.1997.0306a.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
The fructose transporter of the Bacillus subtilis phosphotransferase system consists of two membrane associated (IIA and IIB) and two transmembrane (IIC and IID) subunits [Martin-Verstraete, I., Débarbouille, M., Klier, A. & Rapoport, G. (1990) J. Mol. Biol. 214, 657-671] . It mediates uptake by a mechanism which couples translocation to phosphorylation of the transported solute. The 18-kDa IIBLev subunit transfers phosphoryl groups from His9 of the IIA subunit to the sugar. The three-dimensional structure of IIBLev or similar proteins is not known. IIBLev was overexpressed in Escherichia coli and isotopically labelled with 13C/15N in H2O as well as in 70% D2O. 15N-edited NOESY, 13C-edited NOESY and 13C,15N triple-resonance experiments yielded a nearly complete assignment of the 1H, 13C and 15N resonances. Based on qualitative interpretation of NOE, scalar couplings, chemical shift values and amide exchange data, the secondary structure and topology of IIBLev was determined. IIBLev comprises six parallel beta-strands, one antiparallel beta-strand and 5 alpha-helices. The order of the major secondary-structure elements is (beta alpha)5beta (strand order 7651423). Assuming that the (beta alpha beta)-motives form right-handed turn structures, helices alphaA and alphaB are packed to one face and helices alphaC, alphaD and alphaE to the opposite face of the parallel beta-sheet. His15 which is transiently phosphorylated during catalysis is located in the loop beta1/alphaA of the topological switch point. The amino terminal (beta/alpha)4 part of IIBLev has the same topology as phosphoglyceromutase (PGM; PDB entry 3pgm). Both proteins catalyze phosphoryltransfer reactions which proceed through phosphohistidine intermediates and they show a similar distribution of invariant residues in the topologically equivalent positions of their active sites. The protein fold of IIBLev has no similarity to any of the known structures of other phosphoenolpyruvate-dependent-carbohydrate-phosphotransferase-system proteins.
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Affiliation(s)
- S Seip
- PH-R-Structural Research, Bayer AG, Wuppertal, Germany.
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Chapter 24 Domain and subunit interactions and their role in the function of the E. Coli mannitol transporter, EIIMTL. ACTA ACUST UNITED AC 1996. [DOI: 10.1016/s1383-8121(96)80065-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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