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Zhu W, Iavarone AT, Klinman JP. Hydrogen-Deuterium Exchange Mass Spectrometry Identifies Local and Long-Distance Interactions within the Multicomponent Radical SAM Enzyme, PqqE. ACS CENTRAL SCIENCE 2024; 10:251-263. [PMID: 38435514 PMCID: PMC10906245 DOI: 10.1021/acscentsci.3c01023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/15/2023] [Revised: 12/14/2023] [Accepted: 12/14/2023] [Indexed: 03/05/2024]
Abstract
Interactions among proteins and peptides are essential for many biological activities including the tailoring of peptide substrates to produce natural products. The first step in the production of the bacterial redox cofactor pyrroloquinoline quinone (PQQ) from its peptide precursor is catalyzed by a radical SAM (rSAM) enzyme, PqqE. We describe the use of hydrogen-deuterium exchange mass spectrometry (HDX-MS) to characterize the structure and conformational dynamics in the protein-protein and protein-peptide complexes necessary for PqqE function. HDX-MS-identified hotspots can be discerned in binary and ternary complex structures composed of the peptide PqqA, the peptide-binding chaperone PqqD, and PqqE. Structural conclusions are supported by size-exclusion chromatography coupled to small-angle X-ray scattering (SEC-SAXS). HDX-MS further identifies reciprocal changes upon the binding of substrate peptide and S-adenosylmethionine (SAM) to the PqqE/PqqD complex: long-range conformational alterations have been detected upon the formation of a quaternary complex composed of PqqA/PqqD/PqqE and SAM, spanning nearly 40 Å, from the PqqA binding site in PqqD to the PqqE active site Fe4S4. Interactions among the various regions are concluded to arise from both direct contact and distal communication. The described experimental approach can be readily applied to the investigation of protein conformational communication among a large family of peptide-modifying rSAM enzymes.
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Affiliation(s)
- Wen Zhu
- Department
of Chemistry and Biochemistry, Florida State
University, Tallahassee, Florida 32306, United States
- California
Institute for Quantitative Biosciences, University of California, Berkeley, California 94720, United States
| | - Anthony T. Iavarone
- California
Institute for Quantitative Biosciences, University of California, Berkeley, California 94720, United States
| | - Judith P. Klinman
- California
Institute for Quantitative Biosciences, University of California, Berkeley, California 94720, United States
- Department
of Chemistry, University of California, Berkeley, California 94720, United States
- Department
of Molecular and Cell Biology, University
of California, Berkeley, California 94720, United States
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Abstract
The widely distributed, essential redox factor pyrroloquinoline quinone (PQQ, methoxatin) (1) was discovered in the mid-1960s. The breadth and depth of its biological effects are steadily being revealed, and understanding its biosynthesis at the genomic level is a continuing process. In this review, aspects of the chemistry, biology, biosynthesis, and commercial production of 1 at the gene level, and some applications, are presented from discovery through to mid-2021.
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Affiliation(s)
- Geoffrey A Cordell
- Natural Products Inc., Evanston, Illinois 60202, United States.,Department of Pharmaceutics, College of Pharmacy, University of Florida, Gainesville, Florida 32610, United States
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Zhu W, Klinman JP. Biogenesis of the peptide-derived redox cofactor pyrroloquinoline quinone. Curr Opin Chem Biol 2020; 59:93-103. [PMID: 32731194 PMCID: PMC7736144 DOI: 10.1016/j.cbpa.2020.05.001] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2020] [Revised: 05/04/2020] [Accepted: 05/06/2020] [Indexed: 12/15/2022]
Abstract
Pyrroloquinoline quinone (PQQ) is a peptide-derived redox cofactor produced by prokaryotes that also plays beneficial roles in organisms from other kingdoms. We review recent developments on the pathway of PQQ biogenesis, focusing on the mechanisms of PqqE, PqqF/G, and PqqB. These advances may shed light on other, uncharacterized biosynthetic pathways.
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Affiliation(s)
- Wen Zhu
- California Institute for Quantitative Biosciences and Department of Chemistry, University of California, Berkeley, CA, 94720-3220, USA
| | - Judith P Klinman
- California Institute for Quantitative Biosciences and Department of Chemistry, University of California, Berkeley, CA, 94720-3220, USA; Department of Molecular and Cell Biology, University of California, Berkeley, CA, 94720-3220, USA.
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Zhu W, Walker LM, Tao L, Iavarone AT, Wei X, Britt RD, Elliott SJ, Klinman JP. Structural Properties and Catalytic Implications of the SPASM Domain Iron-Sulfur Clusters in Methylorubrum extorquens PqqE. J Am Chem Soc 2020; 142:12620-12634. [PMID: 32643933 DOI: 10.1021/jacs.0c02044] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Understanding the relationship between the metallocofactor and its protein environment is the key to uncovering the mechanism of metalloenzymes. PqqE, a radical S-adenosylmethionine enzyme in pyrroloquinoline quinone (PQQ) biosynthesis, contains three iron-sulfur cluster binding sites. Two auxiliary iron-sulfur cluster binding sites, designated as AuxI and AuxII, use distinctive ligands compared to other proteins in the family while their functions remain unclear. Here, we investigate the electronic properties of these iron-sulfur clusters and compare the catalytic efficiency of wild-type (WT) Methylorubrum extorquens AM1 PqqE to a range of mutated constructs. Using native mass spectrometry, protein film electrochemistry, and electron paramagnetic resonance spectroscopy, we confirm the previously proposed incorporation of a mixture of [2Fe-2S] and [4Fe-4S] clusters at the AuxI site and are able to assign redox potentials to each of the three iron-sulfur clusters. Significantly, a conservative mutation at AuxI, C268H, shown to selectively incorporate a [4Fe-4S] cluster, catalyzes an enhancement of uncoupled S-adenosylmethionine cleavage relative to WT, together with the elimination of detectable peptide cross-linked product. While a [4Fe-4S] cluster can be tolerated at the AuxI site, the aggregate findings suggest a functional [2Fe-2S] configuration within the AuxI site. PqqE variants with nondestructive ligand replacements at AuxII also show that the reduction potential at this site can be manipulated by changing the electronegativity of the unique aspartate ligand. A number of novel mechanistic features are proposed based on the kinetic and spectroscopic data. Additionally, bioinformatic analyses suggest that the unique ligand environment of PqqE may be relevant to its role in PQQ biosynthesis within an oxygen-dependent biosynthetic pathway.
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Affiliation(s)
- Wen Zhu
- California Institute for Quantitative Biosciences, University of California-Berkeley, Berkeley, California 94720, United States
| | - Lindsey M Walker
- Department of Chemistry, Boston University, Boston, Massachusetts 02215, United States
| | - Lizhi Tao
- Department of Chemistry, University of California-Davis, Davis, California 95616, United States
| | - Anthony T Iavarone
- California Institute for Quantitative Biosciences, University of California-Berkeley, Berkeley, California 94720, United States
| | - Xuetong Wei
- Department of Molecular and Cell Biology, University of California-Berkeley, Berkeley, California 94720, United States
| | - R David Britt
- Department of Chemistry, University of California-Davis, Davis, California 95616, United States
| | - Sean J Elliott
- Department of Chemistry, Boston University, Boston, Massachusetts 02215, United States
| | - Judith P Klinman
- California Institute for Quantitative Biosciences, University of California-Berkeley, Berkeley, California 94720, United States.,Department of Molecular and Cell Biology, University of California-Berkeley, Berkeley, California 94720, United States.,Department of Chemistry, University of California-Berkeley, Berkeley, California 94720, United States
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Latham JA, Barr I, Klinman JP. At the confluence of ribosomally synthesized peptide modification and radical S-adenosylmethionine (SAM) enzymology. J Biol Chem 2017; 292:16397-16405. [PMID: 28830931 DOI: 10.1074/jbc.r117.797399] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Radical S-adenosylmethionine (RS) enzymology has emerged as a major biochemical strategy for the homolytic cleavage of unactivated C-H bonds. At the same time, the post-translational modification of ribosomally synthesized peptides is a rapidly expanding area of investigation. We discuss the functional cross-section of these two disciplines, highlighting the recently uncovered importance of protein-protein interactions, especially between the peptide substrate and its chaperone, which functions either as a stand-alone protein or as an N-terminal fusion to the respective RS enzyme. The need for further work on this class of enzymes is emphasized, given the poorly understood roles performed by multiple, auxiliary iron-sulfur clusters and the paucity of protein X-ray structural data.
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Affiliation(s)
- John A Latham
- From the Department of Chemistry and Biochemistry, University of Denver, Denver, Colorado 80208 and
| | - Ian Barr
- the California Institute of Quantitative Biosciences, University of California at Berkeley, Berkeley, California 94720
| | - Judith P Klinman
- the California Institute of Quantitative Biosciences, University of California at Berkeley, Berkeley, California 94720 .,the Departments of Chemistry and.,Molecular and Cell Biology and
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Evans RL, Latham JA, Xia Y, Klinman JP, Wilmot CM. Nuclear Magnetic Resonance Structure and Binding Studies of PqqD, a Chaperone Required in the Biosynthesis of the Bacterial Dehydrogenase Cofactor Pyrroloquinoline Quinone. Biochemistry 2017; 56:2735-2746. [PMID: 28481092 DOI: 10.1021/acs.biochem.7b00247] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Biosynthesis of the ribosomally synthesized and post-translationally modified peptide (RiPP), pyrroloquinoline quinone (PQQ), is initiated when the precursor peptide, PqqA, is recognized and bound by the RiPP precursor peptide recognition element (RRE), PqqD, for presentation to the first enzyme in the pathway, PqqE. Unlike other RiPP-producing, postribosomal peptide synthesis (PRPS) pathways in which the RRE is a component domain of the first enzyme, PqqD is predominantly a separate scaffolding protein that forms a ternary complex with the precursor peptide and first tailoring enzyme. As PqqD is a stable, independent RRE, this makes the PQQ pathway an ideal PRPS model system for probing RRE interactions using nuclear magnetic resonance (NMR). Herein, we present both the solution NMR structure of Methylobacterium extorquens PqqD and results of 1H-15N HSQC binding experiments that identify the PqqD residues involved in binding the precursor peptide, PqqA, and the enzyme, PqqE. The reported structural model for an independent RRE, along with the mapped binding surfaces, will inform future efforts both to understand and to manipulate PRPS pathways.
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Affiliation(s)
- Robert L Evans
- Department of Biochemistry, Molecular Biology, and Biophysics and Biotechnology Institute, University of Minnesota, Twin Cities , St. Paul, Minnesota 55108, United States
| | - John A Latham
- Department of Chemistry and Department of Molecular and Cell Biology, University of California, Berkeley , Berkeley, California 94720, United States
| | - Youlin Xia
- Minnesota NMR Center, University of Minnesota, Twin Cities , Minneapolis, Minnesota 55455, United States
| | - Judith P Klinman
- Department of Chemistry and Department of Molecular and Cell Biology, University of California, Berkeley , Berkeley, California 94720, United States
| | - Carrie M Wilmot
- Department of Biochemistry, Molecular Biology, and Biophysics and Biotechnology Institute, University of Minnesota, Twin Cities , St. Paul, Minnesota 55108, United States
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