|Gene:||moaA||Accession Numbers: EG11595 (EcoCyc), b0781, ECK0770|
Synonyms: bisA, chlA, chlA1, narA
Molybdenum and tungsten cofactors of all enzymes (except nitrogenase) that require one or the other for activity are present in an oxidized state as molybdate or tungstate ions that are chelated by the cis-dithiolene moiety of a molybdenum cofactor. The cofactor that predominates in E. coli is molybdopterin guanine dinucleotide.
Although much progress has been made in elucidating the biosynthetic pathways for molybdenum cofactors (see the [IobbiNivol13] review), some details remain to be determined. In the first segment 5'-GTP is converted in several steps that involve MoaA and MoaC to a sulfur-free pterin named precursor Z (cyclic pyranopterin phosphate); then in a subsequent series of reactions two sulfhydryl groups are added yielding molybdopterin with its cis-dithiolene moiety; finally molybdenum is inserted via chelation into the cis-dithiolene moiety and a guanyl group is added, yielding molybdopterin guanine dinucleotide.
Enzymes encoded by the moaABCDE, mobAB, mogA, and moeAB operons all participate in the synthesis of molybdopterin guanine dinucleotide. A mutational block in any of these proteins leads to a loss of function of all molybdenum enzymes. Proteins encoded by the moaABCDE operon participate in the first two segments of the biosynthetic pathway, the conversion of a guanosine derivative to precursor Z, and its conversion to molybdopterin.
E. coli MoaA is a member of the radical SAM superfamily [Sofia01]. Although both MoaA and MoaC are involved in the formation of precursor Z (cyclic pyranopterin phosphate), the role of MoaC remains unclear [Wuebbens00]. Using an E. coli strain overproducing MoaA and MoaC, precursor Z was produced, purified, and chemically characterized [SantamariaArauj04]. In earlier work, expression of genes moaABC in a moeA mutant resulted in the production of a product of precursor Z [Rieder98].
moaA, mog (mogA), moaB, moaE, modB, or modC deletion mutants lose the ability to reduce tellurite (tellurate), which can be restored by complementation. Although the E. coli tellurate reductase gene and its product remain uncharacterized, these data suggest that it involves a molybdoenzyme [Theisen13].
The molybdate-sensing transcription regulator ModE acts as an activator for six operons including the moaABCDE operon [Kurata13, Anderson00]. Studies suggest that the mRNA leader of moaA is posttranscriptionally regulated by both the molybdenum cofactor and CsrA [PattersonFortin13, Regulski08].
moaA shows differential codon adaptation, resulting in differential translation efficiency signatures, in thermophilic microbes. It was therefore predicted to play a role in the heat shock response. A moaA deletion mutant was shown to be more sensitive than wild-type specifically to heat shock, but not other stresses [Kri14].
|Map Position: [816,267 -> 817,256] (17.59 centisomes, 63°)||Length: 990 bp / 329 aa|
Molecular Weight of Polypeptide: 37.346 kD (from nucleotide sequence)
Unification Links: ASAP:ABE-0002669 , CGSC:922 , DIP:DIP-10228N , EchoBASE:EB1552 , EcoGene:EG11595 , EcoliWiki:b0781 , Mint:MINT-1229909 , ModBase:P30745 , OU-Microarray:b0781 , PortEco:moaA , PR:PRO_000023260 , Pride:P30745 , Protein Model Portal:P30745 , RefSeq:NP_415302 , RegulonDB:EG11595 , SMR:P30745 , String:511145.b0781 , UniProt:P30745
Relationship Links: InterPro:IN-FAMILY:IPR000385 , InterPro:IN-FAMILY:IPR006638 , InterPro:IN-FAMILY:IPR007197 , InterPro:IN-FAMILY:IPR010505 , InterPro:IN-FAMILY:IPR013483 , InterPro:IN-FAMILY:IPR013785 , Pfam:IN-FAMILY:PF04055 , Pfam:IN-FAMILY:PF06463 , Prosite:IN-FAMILY:PS01305 , Smart:IN-FAMILY:SM00729
In Paralogous Gene Group: 195 (3 members)
|Biological Process:||GO:0009408 - response to heat
GO:0032324 - molybdopterin cofactor biosynthetic process [Johnson87]
GO:0006777 - Mo-molybdopterin cofactor biosynthetic process [UniProtGOA11a, GOA06, GOA01a]
|Molecular Function:||GO:0061597 - cyclic pyranopterin monophosphate synthase activity
GO:0000166 - nucleotide binding [UniProtGOA11a]
GO:0003824 - catalytic activity [GOA01a]
GO:0005525 - GTP binding [UniProtGOA11a]
GO:0016829 - lyase activity [UniProtGOA11a]
GO:0046872 - metal ion binding [UniProtGOA11a, GOA01a]
GO:0051536 - iron-sulfur cluster binding [UniProtGOA11a, GOA01a]
GO:0051539 - 4 iron, 4 sulfur cluster binding [UniProtGOA11a, GOA01a]
|Cellular Component:||GO:0005829 - cytosol
GO:0019008 - molybdopterin synthase complex [GOA01a]
|MultiFun Terms:||metabolism → biosynthesis of building blocks → cofactors, small molecule carriers → molybdenum|
|Growth Medium||Growth?||T (°C)||O2||pH||Osm/L||Growth Observations|
|LB enriched||Yes||37||Aerobic||6.95||Yes [Gerdes03, Comment 1]|
|LB Lennox||Yes||37||Aerobic||7||Yes [Baba06, Comment 2]|
|M9 medium with 1% glycerol||Yes||37||Aerobic||7.2||0.35||Yes [Joyce06, Comment 3]|
|MOPS medium with 0.4% glucose||Yes||37||Aerobic||7.2||0.22||Yes [Baba06, Comment 2]|
Enzymatic reaction of: cyclic pyranopterin monophosphate synthase (molybdopterin biosynthesis protein A)
EC Number: 22.214.171.124
The reaction direction shown, that is, A + B ↔ C + D versus C + D ↔ A + B, is in accordance with the Enzyme Commission system.
The reaction is favored in the direction shown.
In Pathways: molybdenum cofactor biosynthesis
|Protein-Segment||262 -> 264|
10/20/97 Gene b0781 from Blattner lab Genbank (v. M52) entry merged into EcoCyc gene EG11595; confirmed by SwissProt match.
Anderson00: Anderson LA, McNairn E, Lubke T, Pau RN, Boxer DH, Leubke T (2000). "ModE-dependent molybdate regulation of the molybdenum cofactor operon moa in Escherichia coli." J Bacteriol 2000;182(24);7035-43. PMID: 11092866
Baba06: Baba T, Ara T, Hasegawa M, Takai Y, Okumura Y, Baba M, Datsenko KA, Tomita M, Wanner BL, Mori H (2006). "Construction of Escherichia coli K-12 in-frame, single-gene knockout mutants: the Keio collection." Mol Syst Biol 2;2006.0008. PMID: 16738554
DiazMejia09: Diaz-Mejia JJ, Babu M, Emili A (2009). "Computational and experimental approaches to chart the Escherichia coli cell-envelope-associated proteome and interactome." FEMS Microbiol Rev 33(1);66-97. PMID: 19054114
Gerdes03: Gerdes SY, Scholle MD, Campbell JW, Balazsi G, Ravasz E, Daugherty MD, Somera AL, Kyrpides NC, Anderson I, Gelfand MS, Bhattacharya A, Kapatral V, D'Souza M, Baev MV, Grechkin Y, Mseeh F, Fonstein MY, Overbeek R, Barabasi AL, Oltvai ZN, Osterman AL (2003). "Experimental determination and system level analysis of essential genes in Escherichia coli MG1655." J Bacteriol 185(19);5673-84. PMID: 13129938
IobbiNivol13: Iobbi-Nivol C, Leimkuhler S (2013). "Molybdenum enzymes, their maturation and molybdenum cofactor biosynthesis in Escherichia coli." Biochim Biophys Acta 1827(8-9);1086-101. PMID: 23201473
Joyce06: Joyce AR, Reed JL, White A, Edwards R, Osterman A, Baba T, Mori H, Lesely SA, Palsson BO, Agarwalla S (2006). "Experimental and computational assessment of conditionally essential genes in Escherichia coli." J Bacteriol 188(23);8259-71. PMID: 17012394
Kozmin00: Kozmin SG, Pavlov YI, Dunn RL, Schaaper RM (2000). "Hypersensitivity of Escherichia coli Delta(uvrB-bio) mutants to 6-hydroxylaminopurine and other base analogs is due to a defect in molybdenum cofactor biosynthesis." J Bacteriol 182(12);3361-7. PMID: 10852865
Kozmin07: Kozmin SG, Schaaper RM (2007). "Molybdenum cofactor-dependent resistance to N-hydroxylated base analogs in Escherichia coli is independent of MobA function." Mutat Res 619(1-2);9-15. PMID: 17349664
Kurata13: Kurata T, Katayama A, Hiramatsu M, Kiguchi Y, Takeuchi M, Watanabe T, Ogasawara H, Ishihama A, Yamamoto K (2013). "Identification of the set of genes, including nonannotated morA, under the direct control of ModE in Escherichia coli." J Bacteriol 195(19);4496-505. PMID: 23913318
Layer05a: Layer G, Kervio E, Morlock G, Heinz DW, Jahn D, Retey J, Schubert WD (2005). "Structural and functional comparison of HemN to other radical SAM enzymes." Biol Chem 386(10);971-80. PMID: 16218869
McNicholas97: McNicholas PM, Rech SA, Gunsalus RP (1997). "Characterization of the ModE DNA-binding sites in the control regions of modABCD and moaABCDE of Escherichia coli." Mol Microbiol 1997;23(3);515-24. PMID: 9044285
PattersonFortin13: Patterson-Fortin LM, Vakulskas CA, Yakhnin H, Babitzke P, Romeo T (2013). "Dual posttranscriptional regulation via a cofactor-responsive mRNA leader." J Mol Biol 425(19);3662-77. PMID: 23274138
Regulski08: Regulski EE, Moy RH, Weinberg Z, Barrick JE, Yao Z, Ruzzo WL, Breaker RR (2008). "A widespread riboswitch candidate that controls bacterial genes involved in molybdenum cofactor and tungsten cofactor metabolism." Mol Microbiol 68(4);918-32. PMID: 18363797
Rieder98: Rieder C, Eisenreich W, O'Brien J, Richter G, Gotze E, Boyle P, Blanchard S, Bacher A, Simon H (1998). "Rearrangement reactions in the biosynthesis of molybdopterin--an NMR study with multiply 13C/15N labelled precursors." Eur J Biochem 255(1);24-36. PMID: 9692897
Rivers93: Rivers SL, McNairn E, Blasco F, Giordano G, Boxer DH (1993). "Molecular genetic analysis of the moa operon of Escherichia coli K-12 required for molybdenum cofactor biosynthesis." Mol Microbiol 1993;8(6);1071-81. PMID: 8361352
SantamariaArauj04: Santamaria-Araujo JA, Fischer B, Otte T, Nimtz M, Mendel RR, Wray V, Schwarz G (2004). "The tetrahydropyranopterin structure of the sulfur-free and metal-free molybdenum cofactor precursor." J Biol Chem 279(16);15994-9. PMID: 14761975
Sofia01: Sofia HJ, Chen G, Hetzler BG, Reyes-Spindola JF, Miller NE (2001). "Radical SAM, a novel protein superfamily linking unresolved steps in familiar biosynthetic pathways with radical mechanisms: functional characterization using new analysis and information visualization methods." Nucleic Acids Res 29(5);1097-106. PMID: 11222759
Wuebbens00: Wuebbens MM, Liu MT, Rajagopalan K, Schindelin H (2000). "Insights into molybdenum cofactor deficiency provided by the crystal structure of the molybdenum cofactor biosynthesis protein MoaC." Structure Fold Des 8(7);709-18. PMID: 10903949
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