1
|
Sokolovskaya OM, Plessl T, Bailey H, Mackinnon S, Baumgartner MR, Yue WW, Froese DS, Taga ME. Naturally occurring cobalamin (B 12) analogs can function as cofactors for human methylmalonyl-CoA mutase. Biochimie 2020; 183:35-43. [PMID: 32659443 DOI: 10.1016/j.biochi.2020.06.014] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2020] [Revised: 06/26/2020] [Accepted: 06/30/2020] [Indexed: 12/20/2022]
Abstract
Cobalamin, commonly known as vitamin B12, is an essential micronutrient for humans because of its role as an enzyme cofactor. Cobalamin is one of over a dozen structurally related compounds - cobamides - that are found in certain foods and are produced by microorganisms in the human gut. Very little is known about how different cobamides affect B12-dependent metabolism in human cells. Here, we test in vitro how diverse cobamide cofactors affect the function of methylmalonyl-CoA mutase (MMUT), one of two cobalamin-dependent enzymes in humans. We find that, although cobalamin is the most effective cofactor for MMUT, multiple cobamides support MMUT function with differences in binding affinity (Kd), binding kinetics (kon), and concentration dependence during catalysis (KM, app). Additionally, we find that six disease-associated MMUT variants that cause cobalamin-responsive impairments in enzymatic activity also respond to other cobamides, with the extent of catalytic rescue dependent on the identity of the cobamide. Our studies challenge the exclusive focus on cobalamin in the context of human physiology, indicate that diverse cobamides can support the function of a human enzyme, and suggest future directions that will improve our understanding of the roles of different cobamides in human biology.
Collapse
Affiliation(s)
- Olga M Sokolovskaya
- Department of Plant & Microbial Biology, University of California, Berkeley, CA, USA; Department of Chemistry, University of California, Berkeley, CA, USA
| | - Tanja Plessl
- Division of Metabolism and Children's Research Center, University Children's Hospital, Zurich, Switzerland
| | - Henry Bailey
- Structural Genomics Consortium, Nuffield Department of Clinical Medicine, University of Oxford, UK
| | - Sabrina Mackinnon
- Structural Genomics Consortium, Nuffield Department of Clinical Medicine, University of Oxford, UK
| | - Matthias R Baumgartner
- Division of Metabolism and Children's Research Center, University Children's Hospital, Zurich, Switzerland
| | - Wyatt W Yue
- Structural Genomics Consortium, Nuffield Department of Clinical Medicine, University of Oxford, UK
| | - D Sean Froese
- Division of Metabolism and Children's Research Center, University Children's Hospital, Zurich, Switzerland
| | - Michiko E Taga
- Department of Plant & Microbial Biology, University of California, Berkeley, CA, USA.
| |
Collapse
|
2
|
Sokolovskaya OM, Mok KC, Park JD, Tran JLA, Quanstrom KA, Taga ME. Cofactor Selectivity in Methylmalonyl Coenzyme A Mutase, a Model Cobamide-Dependent Enzyme. mBio 2019; 10:e01303-19. [PMID: 31551329 PMCID: PMC6759758 DOI: 10.1128/mbio.01303-19] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2019] [Accepted: 08/23/2019] [Indexed: 12/25/2022] Open
Abstract
Cobamides, a uniquely diverse family of enzyme cofactors related to vitamin B12, are produced exclusively by bacteria and archaea but used in all domains of life. While it is widely accepted that cobamide-dependent organisms require specific cobamides for their metabolism, the biochemical mechanisms that make cobamides functionally distinct are largely unknown. Here, we examine the effects of cobamide structural variation on a model cobamide-dependent enzyme, methylmalonyl coenzyme A (CoA) mutase (MCM). The in vitro binding affinity of MCM for cobamides can be dramatically influenced by small changes in the structure of the lower ligand of the cobamide, and binding selectivity differs between bacterial orthologs of MCM. In contrast, variations in the lower ligand have minor effects on MCM catalysis. Bacterial growth assays demonstrate that cobamide requirements of MCM in vitro largely correlate with in vivo cobamide dependence. This result underscores the importance of enzyme selectivity in the cobamide-dependent physiology of bacteria.IMPORTANCE Cobamides, including vitamin B12, are enzyme cofactors used by organisms in all domains of life. Cobamides are structurally diverse, and microbial growth and metabolism vary based on cobamide structure. Understanding cobamide preference in microorganisms is important given that cobamides are widely used and appear to mediate microbial interactions in host-associated and aquatic environments. Until now, the biochemical basis for cobamide preferences was largely unknown. In this study, we analyzed the effects of the structural diversity of cobamides on a model cobamide-dependent enzyme, methylmalonyl-CoA mutase (MCM). We found that very small changes in cobamide structure could dramatically affect the binding affinity of cobamides to MCM. Strikingly, cobamide-dependent growth of a model bacterium, Sinorhizobium meliloti, largely correlated with the cofactor binding selectivity of S. meliloti MCM, emphasizing the importance of cobamide-dependent enzyme selectivity in bacterial growth and cobamide-mediated microbial interactions.
Collapse
Affiliation(s)
- Olga M Sokolovskaya
- Department of Plant & Microbial Biology, University of California Berkeley, Berkeley, California, USA
- Department of Chemistry, University of California Berkeley, Berkeley, California, USA
| | - Kenny C Mok
- Department of Plant & Microbial Biology, University of California Berkeley, Berkeley, California, USA
| | - Jong Duk Park
- Department of Plant & Microbial Biology, University of California Berkeley, Berkeley, California, USA
| | - Jennifer L A Tran
- Department of Plant & Microbial Biology, University of California Berkeley, Berkeley, California, USA
| | - Kathryn A Quanstrom
- Department of Plant & Microbial Biology, University of California Berkeley, Berkeley, California, USA
| | - Michiko E Taga
- Department of Plant & Microbial Biology, University of California Berkeley, Berkeley, California, USA
| |
Collapse
|
3
|
Pinedo CA, Bringhurst RM, Gage DJ. Sinorhizobium meliloti mutants lacking phosphotransferase system enzyme HPr or EIIA are altered in diverse processes, including carbon metabolism, cobalt requirements, and succinoglycan production. J Bacteriol 2008; 190:2947-56. [PMID: 18281401 PMCID: PMC2293241 DOI: 10.1128/jb.01917-07] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2007] [Accepted: 02/06/2008] [Indexed: 11/20/2022] Open
Abstract
Sinorhizobium meliloti is a member of the Alphaproteobacteria that fixes nitrogen when it is in a symbiotic relationship. Genes for an incomplete phosphotransferase system (PTS) have been found in the genome of S. meliloti. The genes present code for Hpr and ManX (an EIIA(Man)-type enzyme). HPr and EIIA regulate carbon utilization in other bacteria. hpr and manX in-frame deletion mutants exhibited altered carbon metabolism and other phenotypes. Loss of HPr resulted in partial relief of succinate-mediated catabolite repression, extreme sensitivity to cobalt limitation, rapid die-off during stationary phase, and altered succinoglycan production. Loss of ManX decreased expression of melA-agp and lac, the operons needed for utilization of alpha- and beta-galactosides, slowed growth on diverse carbon sources, and enhanced accumulation of high-molecular-weight succinoglycan. A strain with both hpr and manX deletions exhibited phenotypes similar to those of the strain with a single hpr deletion. Despite these strong phenotypes, deletion mutants exhibited wild-type nodulation and nitrogen fixation when they were inoculated onto Medicago sativa. The results show that HPr and ManX (EIIA(Man)) are involved in more than carbon regulation in S. meliloti and suggest that the phenotypes observed occur due to activity of HPr or one of its phosphorylated forms.
Collapse
Affiliation(s)
- Catalina Arango Pinedo
- Department of Molecular and Cell Biology, University of Connecticut, 91 N. Eagleville Rd., U-3125, Storrs, CT 06269-3125, USA
| | | | | |
Collapse
|
4
|
Dunn MF, Araíza G, Mora J. Biochemical characterization of a Rhizobium etli monovalent cation-stimulated acyl-coenzyme A carboxylase with a high substrate specificity constant for propionyl-coenzyme A. MICROBIOLOGY-SGM 2004; 150:399-406. [PMID: 14766918 DOI: 10.1099/mic.0.26779-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Biotin has a profound effect on the metabolism of rhizobia. It is reported here that the activities of the biotin-dependent enzymes acetyl-coenzyme A carboxylase (ACC; EC 6.4.1.2) and propionyl-coenzyme A carboxylase (PCC; EC 6.4.1.3) are present in all species of the five genera comprising the Rhizobiaceae which were examined. Evidence is presented that the ACC and PCC activities detectable in Rhizobium etli extracts are catalysed by a single acyl-coenzyme A carboxylase. The enzyme from R. etli strain 12-53 was purified 478-fold and displayed its highest activity with propionyl-CoA as substrate, with apparent K(m) and V(max) values of 0.064 mM and 2885 nmol min(-1) (mg protein)(-1), respectively. The enzyme carboxylated acetyl-CoA and butyryl-CoA with apparent K(m) values of 0.392 and 0.144 mM, respectively, and V(max) values of 423 and 268 nmol min(-1) (mg protein)(-1), respectively. K(+), or Cs(+) markedly activated the enzyme, which was essentially inactive in their absence. Electrophoretic analysis indicated that the acyl-CoA carboxylase was composed of a 74 kDa biotin-containing alpha subunit and a 45 kDa biotin-free beta subunit, and gel chromatography indicated a total molecular mass of 620 000 Da. The strong kinetic preference of the enzyme for propionyl-CoA is consistent with its participation in an anaplerotic pathway utilizing this substrate.
Collapse
Affiliation(s)
- Michael F Dunn
- Programa de Ingeniería Metabólica, Centro de Investigación sobre Fijación de Nitrógeno, Universidad National Autónoma de México, A. P. 565-A, Cuernavaca, Morelos, Mexico
| | - Gisela Araíza
- Programa de Ingeniería Metabólica, Centro de Investigación sobre Fijación de Nitrógeno, Universidad National Autónoma de México, A. P. 565-A, Cuernavaca, Morelos, Mexico
| | - Jaime Mora
- Programa de Ingeniería Metabólica, Centro de Investigación sobre Fijación de Nitrógeno, Universidad National Autónoma de México, A. P. 565-A, Cuernavaca, Morelos, Mexico
| |
Collapse
|
5
|
|
6
|
Dixon ROD, Wheeler CT. Biochemical, physiological and environmental aspects of symbiotic nitrogen fixation. ACTA ACUST UNITED AC 1983. [DOI: 10.1007/978-94-009-6878-3_5] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/20/2023]
|
7
|
Sato K, Inukai S, Shimizu S. Vitamin B12-dependent methionine synthesis in Rhizobium meliloti. Biochem Biophys Res Commun 1974; 60:723-8. [PMID: 4422142 DOI: 10.1016/0006-291x(74)90300-3] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
|
8
|
Cowles JR, Evans HJ, Russell SA. B12 coenzyme-dependent ribonucleotide reductase in Rhizobium species and the effects of cobalt deficiency on the activity of the enzyme. J Bacteriol 1969; 97:1460-5. [PMID: 5780513 PMCID: PMC249869 DOI: 10.1128/jb.97.3.1460-1465.1969] [Citation(s) in RCA: 53] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
This investigation revealed that the ribonucleotide reductases in extracts of Rhizobium leguminosarum, R. trifolii, R. phaseoli, R. japonicum, and R. meliloti 3DOal (ineffective in nitrogen fixation) are dependent upon B(12) coenzyme for activity. Rhizobium and certain Lactobacillus species are the only two groups of organisms known to contain B(12) coenzyme-dependent ribonucleotide reductases. Extracts of cobalt-deficient R. meliloti cells assayed in the presence of optimum B(12) coenzyme showed a 5- to 10-fold greater ribonucleotide reductase activity than comparable extracts from cells grown on a complete medium. Furthermore, cobalt-deficient cells were abnormally elongated and contained reduced contents of deoxyribonucleic acid. The addition of purified deoxyribonucleosides to cobalt-deficient cultures of R. meliloti failed to alleviate deficiency symptoms.
Collapse
|
9
|
|
10
|
N-Stoffwechsel. ACTA ACUST UNITED AC 1965. [DOI: 10.1007/978-3-642-94914-2_10] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
|