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Warui D, Sil D, Lee KH, Neti SS, Esakova OA, Knox HL, Krebs C, Booker SJ. In Vitro Demonstration of Human Lipoyl Synthase Catalytic Activity in the Presence of NFU1. ACS BIO & MED CHEM AU 2022; 2:456-468. [PMID: 36281303 PMCID: PMC9585516 DOI: 10.1021/acsbiomedchemau.2c00020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Lipoyl synthase (LS) catalyzes the last step in the biosynthesis of the lipoyl cofactor, which is the attachment of sulfur atoms at C6 and C8 of an n-octanoyllysyl side chain of a lipoyl carrier protein (LCP). The protein is a member of the radical S-adenosylmethionine (SAM) superfamily of enzymes, which use SAM as a precursor to a 5'-deoxyadenosyl 5'-radical (5'-dA·). The role of the 5'-dA· in the LS reaction is to abstract hydrogen atoms from C6 and C8 of the octanoyl moiety of the substrate to initiate subsequent sulfur attachment. All radical SAM enzymes have at least one [4Fe-4S] cluster that is used in the reductive cleavage of SAM to generate the 5'-dA·; however, LSs contain an additional auxiliary [4Fe-4S] cluster from which sulfur atoms are extracted during turnover, leading to degradation of the cluster. Therefore, these enzymes catalyze only 1 turnover in the absence of a system that restores the auxiliary cluster. In Escherichia coli, the auxiliary cluster of LS can be regenerated by the iron-sulfur (Fe-S) cluster carrier protein NfuA as fast as catalysis takes place, and less efficiently by IscU. NFU1 is the human ortholog of E. coli NfuA and has been shown to interact directly with human LS (i.e., LIAS) in yeast two-hybrid analyses. Herein, we show that NFU1 and LIAS form a tight complex in vitro and that NFU1 can efficiently restore the auxiliary cluster of LIAS during turnover. We also show that BOLA3, previously identified as being critical in the biosynthesis of the lipoyl cofactor in humans and Saccharomyces cerevisiae, has no direct effect on Fe-S cluster transfer from NFU1 or GLRX5 to LIAS. Further, we show that ISCA1 and ISCA2 can enhance LIAS turnover, but only slightly.
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Affiliation(s)
- Douglas
M. Warui
- Department
of Chemistry and Biochemistry and Molecular Biology and the Howard Hughes
Medical Institute, The Pennsylvania State
University, University
Park, Pennsylvania 16802, United States
| | - Debangsu Sil
- Department
of Chemistry and Biochemistry and Molecular Biology and the Howard Hughes
Medical Institute, The Pennsylvania State
University, University
Park, Pennsylvania 16802, United States
| | - Kyung-Hoon Lee
- Department
of Chemistry and Biochemistry and Molecular Biology and the Howard Hughes
Medical Institute, The Pennsylvania State
University, University
Park, Pennsylvania 16802, United States
| | - Syam Sundar Neti
- Department
of Chemistry and Biochemistry and Molecular Biology and the Howard Hughes
Medical Institute, The Pennsylvania State
University, University
Park, Pennsylvania 16802, United States
| | - Olga A. Esakova
- Department
of Chemistry and Biochemistry and Molecular Biology and the Howard Hughes
Medical Institute, The Pennsylvania State
University, University
Park, Pennsylvania 16802, United States
| | - Hayley L. Knox
- Department
of Chemistry and Biochemistry and Molecular Biology and the Howard Hughes
Medical Institute, The Pennsylvania State
University, University
Park, Pennsylvania 16802, United States
| | - Carsten Krebs
- Department
of Chemistry and Biochemistry and Molecular Biology and the Howard Hughes
Medical Institute, The Pennsylvania State
University, University
Park, Pennsylvania 16802, United States
| | - Squire J. Booker
- Department
of Chemistry and Biochemistry and Molecular Biology and the Howard Hughes
Medical Institute, The Pennsylvania State
University, University
Park, Pennsylvania 16802, United States
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McCarthy EL, Booker SJ. Biochemical Approaches for Understanding Iron-Sulfur Cluster Regeneration in Escherichia coli Lipoyl Synthase During Catalysis. Methods Enzymol 2018; 606:217-239. [PMID: 30097094 DOI: 10.1016/bs.mie.2018.06.006] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Lipoyl synthase (LipA in bacteria) is a radical S-adenosylmethionine (SAM) enzyme that catalyzes the second step of the de novo biosynthesis of the lipoyl cofactor: the insertion of sulfur at C6 and C8 of a pendant octanoyl chain. In addition to the [4Fe4S] cluster that is characteristic of the radical SAM (RS) enzymes, LipA contains a second [4Fe4S] cluster that, though controversial, has been proposed to be degraded during turnover to supply the inserted sulfur atoms. A consequence of this proposed role is that the destruction of its iron-sulfur cluster renders the enzyme in an inactive state. Recently, it was shown that Escherichia coli proteins NfuA or IscU can confer catalytic properties to E. coli LipA in vitro. In this chapter, we present methods for characterizing LipA and analyzing its activity in vitro, and provide strategies to monitor the pathway for the regeneration of LipA's auxiliary cluster by E. coli iron-sulfur carrier protein NfuA.
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Affiliation(s)
- Erin L McCarthy
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA, United States
| | - Squire J Booker
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA, United States; Department of Chemistry, The Pennsylvania State University, University Park, PA, United States; The Howard Hughes Medical Institute, The Pennsylvania State University, University Park, PA, United States.
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3
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McCarthy EL, Booker SJ. Destruction and reformation of an iron-sulfur cluster during catalysis by lipoyl synthase. Science 2018; 358:373-377. [PMID: 29051382 DOI: 10.1126/science.aan4574] [Citation(s) in RCA: 81] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2017] [Accepted: 09/06/2017] [Indexed: 01/15/2023]
Abstract
Lipoyl synthase (LipA) catalyzes the last step in the biosynthesis of the lipoyl cofactor, which is the attachment of two sulfhydryl groups to C6 and C8 of a pendant octanoyl chain. The appended sulfur atoms derive from an auxiliary [4Fe-4S] cluster on the protein that is degraded during turnover, limiting LipA to one turnover in vitro. We found that the Escherichia coli iron-sulfur (Fe-S) cluster carrier protein NfuA efficiently reconstitutes the auxiliary cluster during LipA catalysis in a step that is not rate-limiting. We also found evidence for a second pathway for cluster regeneration involving the E. coli protein IscU. These results show that enzymes that degrade their Fe-S clusters as a sulfur source can nonetheless act catalytically. Our results also explain why patients with NFU1 gene deletions exhibit phenotypes that are indicative of lipoyl cofactor deficiencies.
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Affiliation(s)
- Erin L McCarthy
- Department of Biochemistry and Molecular Biology, Pennsylvania State University, University Park, PA 16802, USA
| | - Squire J Booker
- Department of Biochemistry and Molecular Biology, Pennsylvania State University, University Park, PA 16802, USA. .,Department of Chemistry, Pennsylvania State University, University Park, PA 16802, USA.,Howard Hughes Medical Institute, Pennsylvania State University, University Park, PA 16802, USA
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Abstract
Radical S-adenosylmethionine (SAM) enzymes catalyze an astonishing array of complex and chemically challenging reactions across all domains of life. Of approximately 114,000 of these enzymes, 8 are known to be present in humans: MOCS1, molybdenum cofactor biosynthesis; LIAS, lipoic acid biosynthesis; CDK5RAP1, 2-methylthio-N(6)-isopentenyladenosine biosynthesis; CDKAL1, methylthio-N(6)-threonylcarbamoyladenosine biosynthesis; TYW1, wybutosine biosynthesis; ELP3, 5-methoxycarbonylmethyl uridine; and RSAD1 and viperin, both of unknown function. Aberrations in the genes encoding these proteins result in a variety of diseases. In this review, we summarize the biochemical characterization of these 8 radical S-adenosylmethionine enzymes and, in the context of human health, describe the deleterious effects that result from such genetic mutations.
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Affiliation(s)
- Bradley J Landgraf
- Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802
| | - Erin L McCarthy
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, Pennsylvania 16802
| | - Squire J Booker
- Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802.,Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, Pennsylvania 16802.,The Howard Hughes Medical Institute, The Pennsylvania State University, University Park, Pennsylvania 16802;
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Marsh ENG, Patterson DP, Li L. Adenosyl radical: reagent and catalyst in enzyme reactions. Chembiochem 2010; 11:604-21. [PMID: 20191656 PMCID: PMC3011887 DOI: 10.1002/cbic.200900777] [Citation(s) in RCA: 88] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2009] [Indexed: 12/17/2022]
Abstract
Adenosine is undoubtedly an ancient biological molecule that is a component of many enzyme cofactors: ATP, FADH, NAD(P)H, and coenzyme A, to name but a few, and, of course, of RNA. Here we present an overview of the role of adenosine in its most reactive form: as an organic radical formed either by homolytic cleavage of adenosylcobalamin (coenzyme B(12), AdoCbl) or by single-electron reduction of S-adenosylmethionine (AdoMet) complexed to an iron-sulfur cluster. Although many of the enzymes we discuss are newly discovered, adenosine's role as a radical cofactor most likely arose very early in evolution, before the advent of photosynthesis and the production of molecular oxygen, which rapidly inactivates many radical enzymes. AdoCbl-dependent enzymes appear to be confined to a rather narrow repertoire of rearrangement reactions involving 1,2-hydrogen atom migrations; nevertheless, mechanistic insights gained from studying these enzymes have proved extremely valuable in understanding how enzymes generate and control highly reactive free radical intermediates. In contrast, there has been a recent explosion in the number of radical-AdoMet enzymes discovered that catalyze a remarkably wide range of chemically challenging reactions; here there is much still to learn about their mechanisms. Although all the radical-AdoMet enzymes so far characterized come from anaerobically growing microbes and are very oxygen sensitive, there is tantalizing evidence that some of these enzymes might be active in aerobic organisms including humans.
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Affiliation(s)
- E. Neil G. Marsh
- Department of Chemistry, University of Michigan, Ann Arbor, MI 48109-1055, USA
| | - Dustin P. Patterson
- Department of Chemistry, University of Michigan, Ann Arbor, MI 48109-1055, USA
| | - Lei Li
- Department of Chemistry and Chemical Biology, Indiana University – Purdue University Indianapolis, Indianapolis, IN 46202, USA
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Lee KH, Saleh L, Anton BP, Madinger CL, Benner JS, Iwig DF, Roberts RJ, Krebs C, Booker SJ. Characterization of RimO, a new member of the methylthiotransferase subclass of the radical SAM superfamily. Biochemistry 2009; 48:10162-74. [PMID: 19736993 DOI: 10.1021/bi900939w] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
RimO, encoded by the yliG gene in Escherichia coli, has been recently identified in vivo as the enzyme responsible for the attachment of a methylthio group on the beta-carbon of Asp88 of the small ribosomal protein S12 [Anton, B. P., Saleh, L., Benner, J. S., Raleigh, E. A., Kasif, S., and Roberts, R. J. (2008) Proc. Natl. Acad. Sci. U.S.A. 105, 1826-1831]. To date, it is the only enzyme known to catalyze methylthiolation of a protein substrate; the four other naturally occurring methylthio modifications have been observed on tRNA. All members of the methylthiotransferase (MTTase) family, to which RimO belongs, have been shown to contain the canonical CxxxCxxC motif in their primary structures that is typical of the radical S-adenosylmethionine (SAM) family of proteins. MiaB, the only characterized MTTase, and the enzyme experimentally shown to be responsible for methylthiolation of N(6)-isopentenyladenosine of tRNA in E. coli and Thermotoga maritima, has been demonstrated to harbor two distinct [4Fe-4S] clusters. Herein, we report in vitro biochemical and spectroscopic characterization of RimO. We show by analytical and spectroscopic methods that RimO, overproduced in E. coli in the presence of iron-sulfur cluster biosynthesis proteins from Azotobacter vinelandii, contains one [4Fe-4S](2+) cluster. Reconstitution of this form of RimO (RimO(rcn)) with (57)Fe and sodium sulfide results in a protein that contains two [4Fe-4S](2+) clusters, similar to MiaB. We also show by mass spectrometry that RimO(rcn) catalyzes the attachment of a methylthio group to a peptide substrate analogue that mimics the loop structure bearing aspartyl 88 of the S12 ribosomal protein from E. coli. Kinetic analysis of this reaction shows that the activity of RimO(rcn) in the presence of the substrate analogue does not support a complete turnover. We discuss the possible requirement for an assembled ribosome for fully active RimO in vitro. Our findings are consistent with those of other enzymes that catalyze sulfur insertion, such as biotin synthase, lipoyl synthase, and MiaB.
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Affiliation(s)
- Kyung-Hoon Lee
- Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, USA
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Szu PH, Ruszczycky MW, Choi SH, Yan F, Liu HW. Characterization and mechanistic studies of DesII: a radical S-adenosyl-L-methionine enzyme involved in the biosynthesis of TDP-D-desosamine. J Am Chem Soc 2009; 131:14030-42. [PMID: 19746907 PMCID: PMC2780582 DOI: 10.1021/ja903354k] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
D-desosamine (1) is a 3-(N,N-dimethylamino)-3,4,6-trideoxyhexose found in a number of macrolide antibiotics including methymycin (2), neomethymycin (3), pikromycin (4), and narbomycin (5) produced by Streptomyces venezuelae . It plays an essential role in conferring biological activities to its parent aglycones. Previous genetic and biochemical studies of the biosynthesis of desosamine in S. venezuelae showed that the conversion of TDP-4-amino-4,6-dideoxy-D-glucose (8) to TDP-3-keto-4,6-dideoxy-D-glucose (9) is catalyzed by DesII, which is a member of the radical S-adenosyl-L-methionine (SAM) enzyme superfamily. Here, we report the purification and reconstitution of His(6)-tagged DesII, characterization of its [4Fe-4S] cluster using UV-vis and EPR spectroscopies, and the capability of flavodoxin, flavodoxin reductase, and NADPH to reduce the [4Fe-4S](2+) cluster. Also included are a steady-state kinetic analysis of DesII-catalyzed reaction and an investigation of the substrate flexibility of DesII. Studies of deuterium incorporation into SAM using TDP-[3-(2)H]-4-amino-4,6-dideoxy-D-glucose as the substrate provides strong evidence for direct hydrogen atom transfer to a 5'-deoxyadenosyl radical in the catalytic cycle. The fact that hydrogen atom abstraction occurs at C-3 also sheds light on the mechanism of this intriguing deamination reaction.
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Affiliation(s)
- Ping-Hui Szu
- Division of Medicinal Chemistry, College of Pharmacy, and Department of Chemistry and Biochemistry, University of Texas at Austin, Austin, Texas 78712, USA
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Booker SJ, Cicchillo RM, Grove TL. Self-sacrifice in radical S-adenosylmethionine proteins. Curr Opin Chem Biol 2007; 11:543-52. [PMID: 17936058 DOI: 10.1016/j.cbpa.2007.08.028] [Citation(s) in RCA: 95] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2007] [Revised: 08/22/2007] [Accepted: 08/22/2007] [Indexed: 01/10/2023]
Abstract
The radical SAM superfamily of metalloproteins catalyze the reductive cleavage of S-adenosyl-l-methionine to generate a 5'-deoxyadenosyl radical (5'-dA*) intermediate that is obligate for turnover. The 5'-dA* acts as a potent oxidant, initiating turnover by abstracting a hydrogen atom from an appropriate substrate. A special class of these enzymes use this strategy to functionalize unactivated C-H bonds by insertion of sulfur atoms. This review will describe the characterization of three members of this class - biotin synthase, lipoyl synthase, and MiaB protein - each of which has been shown to cannibalize itself during turnover.
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Affiliation(s)
- Squire J Booker
- Department of Chemistry, The Pennsylvania State University, University Park, PA 16803, United States.
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