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Qiu S, Xu D, Xu M, Zhou H, Sun N, Zhang L, Zhao M, He J, Ran T, Sun B, Wang W. Crystal structures of PigF, an O-methyltransferase involved in the prodigiosin synthetic pathway, reveal an induced-fit substrate-recognition mechanism. IUCRJ 2022; 9:316-327. [PMID: 35371495 PMCID: PMC8895007 DOI: 10.1107/s2052252521011696] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/13/2021] [Accepted: 11/04/2021] [Indexed: 06/14/2023]
Abstract
Prodigiosin, a red linear tripyrrole pigment, is a typical secondary metabolite with numerous biological functions, such as anticancer, antibacterial and immunosuppressant activities, and is synthesized through a bifurcated biosynthesis pathway from 4-methoxy-2,2'-bipyrrole-5-carbaldehyde (MBC) and 2-methyl-3-n-amylpyrrole (MAP). The last step in the biosynthetic pathway of MBC is catalysed by PigF, which transfers a methyl group to 4-hydroxy-2,20-bipyrrole-5-carbaldehyde (HBC) to form the final product MBC. However, the catalytic mechanism of PigF is still elusive. In this study, crystal structures of apo PigF and S-adenosylhomocysteine (SAH)-bound PigF were determined. PigF forms a homodimer and each monomer consists of two domains: a C-terminal catalytic domain and an N-terminal dimerization domain. Apo PigF adopts an open conformation, while the structure of the complex with the product SAH adopts a closed conformation. The binding of SAH induces dramatic conformational changes of PigF, suggesting an induced-fit substrate-binding mechanism. Further structural comparison suggests that this induced-fit substrate-recognition mechanism may generally exist in O-methyltransferases. Docking and mutation studies identified three key residues (His98, His247 and Asp248) that are crucial for enzyme activity. The essential function of His247 and Asp248 and structure analysis suggests that both residues are involved in activation of the HBC substrate of PigF. The invariance of Asp248 in PigF further confirmed its essential role. The invariance and essential role of His98 in PigF suggests that it is involved in correctly positioning the substrate. This study provides new insight into the catalytic mechanism of PigF, reveals an induced-fit substrate-recognition model for PigF and broadens the understanding of O-methyltransferases.
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Affiliation(s)
- Shenshen Qiu
- Department of Microbiology, College of Life Sciences, Nanjing Agricultural University, Nanjing 210095, People’s Republic of China
| | - Dongqing Xu
- Department of Microbiology, College of Life Sciences, Nanjing Agricultural University, Nanjing 210095, People’s Republic of China
| | - Mengxue Xu
- Department of Microbiology, College of Life Sciences, Nanjing Agricultural University, Nanjing 210095, People’s Republic of China
- Shanghai Synchrotron Radiation Facility, Shanghai Advanced Research Institute, Chinese Academy of Sciences, Shanghai 201204, People’s Republic of China
| | - Huan Zhou
- Shanghai Synchrotron Radiation Facility, Shanghai Advanced Research Institute, Chinese Academy of Sciences, Shanghai 201204, People’s Republic of China
| | - Ning Sun
- Department of Microbiology, College of Life Sciences, Nanjing Agricultural University, Nanjing 210095, People’s Republic of China
| | - Li Zhang
- Department of Microbiology, College of Life Sciences, Nanjing Agricultural University, Nanjing 210095, People’s Republic of China
| | - Mengmeng Zhao
- Department of Microbiology, College of Life Sciences, Nanjing Agricultural University, Nanjing 210095, People’s Republic of China
| | - Jianhua He
- Shanghai Synchrotron Radiation Facility, Shanghai Advanced Research Institute, Chinese Academy of Sciences, Shanghai 201204, People’s Republic of China
| | - Tingting Ran
- Department of Microbiology, College of Life Sciences, Nanjing Agricultural University, Nanjing 210095, People’s Republic of China
| | - Bo Sun
- Shanghai Synchrotron Radiation Facility, Shanghai Advanced Research Institute, Chinese Academy of Sciences, Shanghai 201204, People’s Republic of China
| | - Weiwu Wang
- Department of Microbiology, College of Life Sciences, Nanjing Agricultural University, Nanjing 210095, People’s Republic of China
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Qiu S, Jia S, Zhang F, Liu X, Ran T, Wang W, Wang C, Xu D. Two component system CpxR/A regulates the prodigiosin biosynthesis by negative control in Serratia marcescens FS14. Biochem Biophys Res Commun 2021; 579:136-140. [PMID: 34600298 DOI: 10.1016/j.bbrc.2021.09.050] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2021] [Accepted: 09/20/2021] [Indexed: 11/30/2022]
Abstract
Prodigiosin is a tripyrrole red secondary metabolite synthesized by many microorganisms, including Serratia marcescens. In this study, we found that the deletion of the gene of sensor kinase CpxA dramatically decreased the prodigiosin production, while the deletion of the gene of the response regulator CpxR or both genes of CpxRA has no effect on prodigiosin production, the kinase function of CpxA is not essential for its regulation on prodigiosin production while the phosphorylation site of CpxR is required. We further demonstrated that the CpxA regulates the prodigiosin biosynthesis at the transcriptional level and the phosphatase activity of CpxA plays vital roles in the regulation of prodigiosin biosynthesis. Finally, we proposed that CpxR/A regulates the prodigiosin biosynthesis by negative control and the phosphorylation level of CpxR may determine the positive or negative control of the genes it regulated.
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Affiliation(s)
- Shenshen Qiu
- Laboratory of Microbiological Engineering of Agricultural Environment of Ministry of Agriculture, Department of Microbiology, College of Life Sciences, Nanjing Agricultural University, Nanjing, China
| | - Shanshan Jia
- Laboratory of Microbiological Engineering of Agricultural Environment of Ministry of Agriculture, Department of Microbiology, College of Life Sciences, Nanjing Agricultural University, Nanjing, China
| | - Fan Zhang
- Laboratory of Microbiological Engineering of Agricultural Environment of Ministry of Agriculture, Department of Microbiology, College of Life Sciences, Nanjing Agricultural University, Nanjing, China
| | - Xia Liu
- Laboratory of Microbiological Engineering of Agricultural Environment of Ministry of Agriculture, Department of Microbiology, College of Life Sciences, Nanjing Agricultural University, Nanjing, China
| | - Tingting Ran
- Laboratory of Microbiological Engineering of Agricultural Environment of Ministry of Agriculture, Department of Microbiology, College of Life Sciences, Nanjing Agricultural University, Nanjing, China
| | - Weiwu Wang
- Laboratory of Microbiological Engineering of Agricultural Environment of Ministry of Agriculture, Department of Microbiology, College of Life Sciences, Nanjing Agricultural University, Nanjing, China.
| | - Changlin Wang
- Institute of Chinese Medicinal Materials, Nanjing Agricultural University, Nanjing, China.
| | - Dongqing Xu
- Laboratory of Microbiological Engineering of Agricultural Environment of Ministry of Agriculture, Department of Microbiology, College of Life Sciences, Nanjing Agricultural University, Nanjing, China.
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Crystal structure of PppA from Pseudomonas aeruginosa, a key regulatory component of type VI secretion systems. Biochem Biophys Res Commun 2019; 516:196-201. [PMID: 31208722 DOI: 10.1016/j.bbrc.2019.06.020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2019] [Accepted: 06/03/2019] [Indexed: 11/20/2022]
Abstract
The Type VI secretion system (T6SS) is a membrane protein complex related to inter-bacterial competitions and host-pathogen interactions in Pseudomonas aeruginosa. The T6SS is regulated by a great variety of regulatory mechanisms at multiple levels, including post-translational modification with threonine phosphorylation mediated by Ser/Thr protein kinase PpkA and phosphatase PppA. The T6SS is activated by PpkA via Thr phosphorylation of Fha, and PppA can antagonize PpkA. PppA is a PP2C-family protein phosphatase and plays a key role in the disassembly and reassembly of T6SS organelles. Herein, we report the first crystal structure of PppA from Pseudomonas aeruginosa, which was determined at a resolution of 2.10 Å. The overall structure consists of a bacteria PPM structural core and a flexible flap subdomain. PppA harbors a catalytic pocket containing two manganese ions which correspond to the canonical dinuclear metal center of Ser/Thr protein phosphatases including the bacterial PPM phosphatases and human PP2C. The flexibility and the diversity of the sequence of flap subdomain across the homologues might provide clues for substrates specific recognition of phosphatases.
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Li P, Wang J, Zou Y, Sun Z, Zhang M, Geng Z, Xu W, Wang D. Interaction of Hsp90AA1 with phospholipids stabilizes membranes under stress conditions. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2019; 1861:457-465. [DOI: 10.1016/j.bbamem.2018.11.009] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/05/2018] [Revised: 11/19/2018] [Accepted: 11/26/2018] [Indexed: 01/29/2023]
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Wang X, Sun B, Xu M, Qiu S, Xu D, Ran T, He J, Wang W. Crystal structure of the periplasmic domain of TssL, a key membrane component of Type VI secretion system. Int J Biol Macromol 2018; 120:1474-1479. [PMID: 30266644 DOI: 10.1016/j.ijbiomac.2018.09.166] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2018] [Revised: 09/15/2018] [Accepted: 09/25/2018] [Indexed: 11/18/2022]
Abstract
Type VI secretion system (T6SS), as a macromolecular system, is commonly found in Gram-negative bacteria and responsible for exporting effectors. T6SS consists of 13 core proteins. TssL is a component of the membrane complex and plays a pivotal role in T6SS. Here, we report the crystal structure of the C-terminal periplasmic domain of TssL (TssLCter) from Serratia marcescens FS14. The TssLCter (310-503) contain a five-stranded anti-parallel β-sheet flanked by five α-helices and a short N-terminal helix. Structural comparisons revealed that it belongs to the OmpA-like family with a remarked difference in the conformation of the loop3-5. In OmpA-like family, the corresponding loop is located close to loop2-3, forming a cavity with a small opening together with the longest α5, whereas in TssLCter, loop3-5 flipped away from this cavity region. In addition, significant differences in the peptidoglycan (PG) binding site suggest that big conformational change must take place to accomplish the PG binding for TssLCter. Furthermore, a long flexible loop between helices α1 and α2 is unique in TssL. TssL would have a big conformational change during the delivery of the Hcp needle and effectors. So we speculate that the long flexible endows TssL the adaptation of its evolutionary new function.
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Affiliation(s)
- Xiangbei Wang
- Key Laboratory of Microbiological Engineering of Agricultural Environment of Ministry of Agriculture, Department of Microbiology, College of Life Sciences, Nanjing Agricultural University, Nanjing, China
| | - Bo Sun
- Shanghai Institute of Applied Physics, Chinese Academy of Sciences, 201204 Shanghai, China
| | - Mengxue Xu
- Key Laboratory of Microbiological Engineering of Agricultural Environment of Ministry of Agriculture, Department of Microbiology, College of Life Sciences, Nanjing Agricultural University, Nanjing, China
| | - Shenshen Qiu
- Key Laboratory of Microbiological Engineering of Agricultural Environment of Ministry of Agriculture, Department of Microbiology, College of Life Sciences, Nanjing Agricultural University, Nanjing, China
| | - Dongqing Xu
- Key Laboratory of Microbiological Engineering of Agricultural Environment of Ministry of Agriculture, Department of Microbiology, College of Life Sciences, Nanjing Agricultural University, Nanjing, China
| | - Tingting Ran
- Key Laboratory of Microbiological Engineering of Agricultural Environment of Ministry of Agriculture, Department of Microbiology, College of Life Sciences, Nanjing Agricultural University, Nanjing, China.
| | - Jianhua He
- Shanghai Institute of Applied Physics, Chinese Academy of Sciences, 201204 Shanghai, China.
| | - Weiwu Wang
- Key Laboratory of Microbiological Engineering of Agricultural Environment of Ministry of Agriculture, Department of Microbiology, College of Life Sciences, Nanjing Agricultural University, Nanjing, China.
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