>TIGR02082 metH methionine synthase; InterPro: IPR011822 Vitamin B12 dependent methionine synthase 2.1.1.13 from EC (5-methyltetrahydrofolate--homocysteine S-methyltransferase) catalyses the conversion of 5-methyltetrahydrofolate and L-homocysteine to tetrahydrofolate and L-methionine as the final step in de novo methionine biosynthesis. The enzyme requires methylcobalamin as a cofactor. In humans, defects in this enzyme are the cause of autosomal recessive inherited methylcobalamin deficiency (CBLG), which causes mental retardation, macrocytic anemia and homocystinuria. Mild deficiencies in activity may result in mild hyperhomocysteinemia, and mutations in the enzyme may be involved in tumorigenesis. Vitamin B12 dependent methionine synthase is found in prokaryotes and eukaryotes, but in prokaryotes the cofactor is cobalamin. This enzyme is a large protein composed of four structurally and functionally distinct modules: the first two modules bind homocysteine and tetrahydrofolate , the third module binds the B12 cofactor , and the C-terminal module (activation domain) binds S-adenosylmethionine. The activation domain is essential for the reductive activation of the enzyme. During the catalytic cycle, the highly reactive cob(I)alamin intermediate can be oxidised to produce an inactive cob(II)alamin enzyme; the enzyme is then reactivated via reductive methylation by the activation domain . The activation domain adopts an unusual alpha/beta fold.Recent studies suggest that this enzyme exists as an ensemble of conformations with equilibria dependent on the oxidation and methylation state of the cobalamin and on the concentrations of substrates or products .; GO: 0008705 methionine synthase activity, 0031419 cobalamin binding, 0050897 cobalt ion binding, 0009086 methionine biosynthetic process.

Probab=96.47 E-value=0.051 Score=35.30 Aligned_cols=258 Identities=15% Similarity=0.164 Sum_probs=146.5 Q ss_pred CCCHHHHH----HHHHHHHHCCCCEEEECCCCCCHHCCCHHHHHHHH--HHHHHCCCCCCCCCCC-CCCCHH------HH Q ss_conf 86899999----99999997699899986723250108999999986--5431101234430036-741027------89 Q gi|254780276|r 18 LIDEDAFV----EHIEWQITEGSGGLVPAGTTGESSTLSHEEHCRII--ELCVKTVASRVPVMAG-IGSNNT------RE 84 (292) Q Consensus 18 ~iD~~~~~----~~i~~l~~~gv~gi~~~G~tGE~~~Ls~~Er~~~~--~~~~~~~~~r~pii~g-v~~~~~------~~ 84 (292) T Consensus 142 nvtyD~L~~AY~e~~~gL~dGGvDllLi-----ET~fDtLnaKAAlfA~~~~F~~~g~~lPi~iSGti~d~sGr~LsGqt 216 (1265) T TIGR02082 142 NVTYDELVDAYKEQIKGLLDGGVDLLLI-----ETVFDTLNAKAALFAAETVFEEKGRELPIMISGTIVDTSGRTLSGQT 216 (1265) T ss_pred CCCHHHHHHHHHHHHHHHHHCCCHHHHH-----HHHHHHHHHHHHHHHHHHHHHHCCCCCCEEEEEEEECCCCCCCCCCC T ss_conf 5787989999999999877326035477-----47999999999999999999972897876886026227687202620 Q ss_pred HHHHHHHHHHCCCCCCCEECCCCCCCCHHHHHHHHHHHHHHHCCCCEEEEC---HHHCC----CCCCHHHHHHHHHHCC- Q ss_conf 999753432102443200123433431788999999987530233012100---11111----2111068999743203- Q gi|254780276|r 85 SVELAQYAHSIGADALLVVIPYYNKPNRRGLLAHFGEIATTVSSPIYIYNN---PSRTV----IEMDVDTMAELAATYP- 156 (292) Q Consensus 85 ~i~~a~~a~~~Gad~i~v~~P~~~~~~~~~i~~~~~~i~~~~~~pi~iYn~---P~~~g----~~~~~~~l~~L~~~~p- 156 (292) T Consensus 217 ~~Af~~sl~~~~~~~i--GL--NCAlGpdel~~h~~~Ls~~~~~~Vs~~PNAGLPn~~G~~AeY~l~P~~~A~~l~~fa~ 292 (1265) T TIGR02082 217 LEAFLASLEHAEILII--GL--NCALGPDELRPHVKELSEHAEAYVSVHPNAGLPNAFGKQAEYDLTPDELAKALKDFAE 292 (1265) T ss_pred HHHHHHHHCCCCCCEE--CC--CCCCCHHHHHHHHHHHHHHCCEEEEEECCCCCCCCCCCCCCCCCCHHHHHHHHHHHHH T ss_conf 8999998546873024--12--3114777899999998700881388833788810047776875557899999999998 Q ss_pred ----HHHHHHCCCC-CHHHHHHHH---HHC-CCCEEE--CCCC-CCCHHHHHHHCCCCCCCCC---CCCCCCHHHHHHHH Q ss_conf ----0233100122-113589999---735-984032--0132-2100124320334455222---23211002444443 Q gi|254780276|r 157 ----NIVGVKDATG-KIELVSEQR---LSC-GFDFIQ--LSGE-DSSALGFNAHGGVGCISVT---ANVVPRICAEFQQA 221 (292) Q Consensus 157 ----ni~giK~~~~-~~~~~~~~~---~~~-~~~~~v--~~G~-~~~~~~~~~~G~~G~is~~---~n~~P~~~~~l~~~ 221 (292) T Consensus 293 eg~lniVG--GCCGTTP~HIraiA~aVk~i~Pr~~~~ta~~~~~~~Sgle~~~~~~~~~FvniGERtNv~--GS~KF~~l 368 (1265) T TIGR02082 293 EGGLNIVG--GCCGTTPDHIRAIAEAVKDIKPRKRPETALYEPSRLSGLEAITIAQESNFVNIGERTNVA--GSKKFRKL 368 (1265) T ss_pred HCCEEEEE--CCCCCCHHHHHHHHHHHHCCCCCCCCCCCCCHHHHHHCCCCCCCCCCCCEEEEEEEECCC--CCHHHHHH T ss_conf 63903774--268996789999999981687688876556324676303134636635668874300787--68679998 Q ss_pred HCCCCCHHHHHHHHH-HHH---HHHHHHCCC---CHHHHHHHHHHCCCCCCCCC-CCCCCCCCCHHHHHHHHHHHHHCC Q ss_conf 117882799999999-999---999984268---93899999998698899876-788889879899999999998559 Q gi|254780276|r 222 MIRGDYRQALLYQDK-LMP---LHQALFMEP---AVCCVKYALSRLGRNVSLAV-RSPMVSTLEKDTMIAIDQALERLG 292 (292) Q Consensus 222 ~~~gd~~~A~~l~~~-l~~---l~~~~~~~~---~~~~~K~~l~~~G~~~~~~~-R~Pl~~~~~~e~~~~i~~~l~~lG 292 (292) T Consensus 369 i~aedY~~~L~iAk~QV~~GAQilDiN~D~~~lDg~~~M~~f~~llA~eP--dia~vPl-Ml-DSs~~~vleaGLk~~q 443 (1265) T TIGR02082 369 IIAEDYDEALDIAKQQVENGAQILDINVDDGMLDGVAAMKRFLNLLASEP--DIAKVPL-ML-DSSEWEVLEAGLKCIQ 443 (1265) T ss_pred HHCCCHHHHHHHHHHHHHCCCEEEEEEECCCCCCCHHHHHHHHHHHCCCC--CCCCCCC-CC-CCCHHHHHHHHHHHCC T ss_conf 51238468878988871169779898706553673789999999626898--6021360-00-5743799976243038

HHsearch alignment for GI: 254780276 and conserved domain: TIGR02082