>TIGR02090 LEU1_arch isopropylmalate/citramalate/homocitrate synthases; InterPro: IPR011830 Methanogenic archaea contain three closely related homologs of the 2-isopropylmalate synthases (LeuA) represented by IPR005671 from INTERPRO. Two of these in Methanococcus janaschii (MJ1392 - CimA ; MJ0503 - AksA ) have been characterised as catalyzing alternative reactions leaving the third (MJ1195) as the presumptive LeuA enzyme. CimA is citramalate (2-methylmalate) synthase, which condenses acetyl-CoA with pyruvate. This enzyme is believed to be involved in the biosynthesis of isoleucine in methanogens and possibly other species lacking threonine dehydratase. AksA is a homocitrate synthase which also produces (homo)2-citrate and (homo)3-citrate in the biosynthesis of Coenzyme B which is restricted solely to methanogenic archaea. Methanogens, then should and apparently do contain all three of these enzymes. Unfortunately, phylogenetic trees do not resolve into three unambiguous clades, making assignment of function to particular genes problematic. Other archaea, which lack a threonine dehydratase (mainly Euryarchaeota), should contain both CimA and LeuA genes. This is true for archaeoglobus fulgidis, but not for the Pyrococci which have none in this clade, but one in IPR005671 from INTERPRO and one in IPR005675 from INTERPRO which may fulfil these roles. Proteins from other species, which have only one hit to this entry and lack threonine dehydratase, are very likely to be LeuA enzymes.; GO: 0046912 transferase activity transferring acyl groups acyl groups converted into alkyl on transfer, 0019752 carboxylic acid metabolic process.

Probab=90.24 E-value=1.5 Score=23.76 Aligned_cols=135 Identities=24% Similarity=0.382 Sum_probs=86.4 Q ss_pred CCCCEEEEEEC-----CCHHHHHHHHHHHHCCCCCEEEE--CCCCCHHHHHHHHHHHHHHHHHHHHHHHHHHHHCCCC-- Q ss_conf 57846999826-----99899999887531045377744--2564136776668899998558999999999850279-- Q gi|254781167|r 46 QEKPLALQIGG-----ADISKLVEAAKIVEDFGYNEINL--NVGCPSARVHEGSFGACLMLNPDIVGDCIAAMCKALS-- 116 (322) Q Consensus 46 ~e~p~~~Ql~g-----~~p~~~~~aa~~~~~~g~~~idl--N~GCP~~~v~~~g~GaaLl~~p~~~~~iv~~~~~~~~-- 116 (322) T Consensus 124 KEHGLiVEfSAEDATRtd~dfLIk~~k~A~eAGADRi~~~DTVGV---------------~~P~km~~l~k~~k~~~kKd 188 (371) T TIGR02090 124 KEHGLIVEFSAEDATRTDIDFLIKVFKKAEEAGADRINVADTVGV---------------LTPQKMEELIKKIKENVKKD 188 (371) T ss_pred HHCCCEEEECCCCCCCCCHHHHHHHHHHHHHCCCCEEEECCCCCC---------------CCHHHHHHHHHHHHHHHCCC T ss_conf 525735531778876586789999987133216777550785563---------------68267999999999863588 Q ss_pred EEEEEEEECCCCCCCCCCCHHHHHHHHC--CCCCCHHHHHHHHHHHHCCCCCCCCCCCCCHHHHH-H------------- Q ss_conf 0699986113456653220145543200--01220121001356640257742122766104678-7------------- Q gi|254781167|r 117 IPVTVKCRIGVDDQIPAVALRNLVKSIK--KSGVNGIWIHARKAILKGLSPKDNRKIPNLDYDIV-Y------------- 180 (322) Q Consensus 117 ~pvsvK~RlG~~~~~~~~~~~~~~~~~~--~~g~~~itiH~Rt~~~~g~s~~~~~~~~~~~~~~i-~------------- 180 (322) T Consensus 189 ~~~sVHCH--------NDFGlAtANsi~gv~aGA~~v--H~-T--vNGiGER----AGNAaLEEVV~AL~~LYG~~~~IK 251 (371) T TIGR02090 189 LPVSVHCH--------NDFGLATANSIAGVLAGAEQV--HV-T--VNGIGER----AGNAALEEVVMALKVLYGVDTKIK 251 (371) T ss_pred CCEEEEEE--------CCCCHHHHHHHHHHHCCCEEE--EE-E--ECCCCCC----HHHHHHHHHHHHHHHHCCCCCCCC T ss_conf 70588620--------860188999999972283577--35-5--5576101----345889999999898714102445 Q ss_pred --------HHHHHCCCCCCCCCCCCCCHHHHHHHHHC--CCCE Q ss_conf --------66673887530257777899898887420--3523 Q gi|254781167|r 181 --------EIKKENPDLFIGLNGGLEDMSQALKILPS--VDGV 213 (322) Q Consensus 181 --------~l~~~~~~~~i~~NGdi~~~~~a~~~l~~--~dgv 213 (322) T Consensus 252 ~ekLYE~SrlVs~l~~~~VPpNKaIVG-eNAFaHEsGIHv~gv 293 (371) T TIGR02090 252 TEKLYETSRLVSKLSGVKVPPNKAIVG-ENAFAHESGIHVDGV 293 (371) T ss_pred CCCCCHHHHHHHHHCCCCCCCCCCCCC-CCCCCCCCHHHHHHH T ss_conf 300201777899871788889677325-650001103558887

HHsearch alignment for GI: 254781167 and conserved domain: TIGR02090