>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=92.59  E-value=0.98  Score=25.97  Aligned_cols=110  Identities=15%  Similarity=0.089  Sum_probs=82.5

Q ss_pred             HHHHHHHHHHHCCCCEEEECCCCCCHH------CCCHHHHHHHHHHHHHCCCCCCCCC-CC---CCCCHHHHHHHHHHHH
Q ss_conf             999999999976998999867232501------0899999998654311012344300-36---7410278999975343
Q gi|254780276|r   23 AFVEHIEWQITEGSGGLVPAGTTGESS------TLSHEEHCRIIELCVKTVASRVPVM-AG---IGSNNTRESVELAQYA   92 (292)
Q Consensus        23 ~~~~~i~~l~~~gv~gi~~~G~tGE~~------~Ls~~Er~~~~~~~~~~~~~r~pii-~g---v~~~~~~~~i~~a~~a   92 (292)
T Consensus        73 A~k~DID~AidcgvdsIh~fiaTSpiH~KYKl~~K~~devle~~veAvEYAKEHGLiVEfSAEDATRtd~dfLIk~~k~A  152 (371)
T TIGR02090        73 ALKKDIDKAIDCGVDSIHTFIATSPIHLKYKLKNKSRDEVLEKAVEAVEYAKEHGLIVEFSAEDATRTDIDFLIKVFKKA  152 (371)
T ss_pred             CCCCCHHHHHHCCCCEEEEEECCCHHHHHCCCCCCCHHHHHHHHHHHHHHHHHCCCEEEECCCCCCCCCHHHHHHHHHHH
T ss_conf             67310015643698778998048857872348887899999999998987752573553177887658678999998713


Q ss_pred             HHCCCCCCCEECCCCCCCCHHHHHHHHHHHHHHHC--CCCEEE
Q ss_conf             21024432001234334317889999999875302--330121
Q gi|254780276|r   93 HSIGADALLVVIPYYNKPNRRGLLAHFGEIATTVS--SPIYIY  133 (292)
Q Consensus        93 ~~~Gad~i~v~~P~~~~~~~~~i~~~~~~i~~~~~--~pi~iY  133 (292)
T Consensus       153 ~eAGADRi~~~DT-VGV~~P~km~~l~k~~k~~~kKd~~~sVH  194 (371)
T TIGR02090       153 EEAGADRINVADT-VGVLTPQKMEELIKKIKENVKKDLPVSVH  194 (371)
T ss_pred             HHCCCCEEEECCC-CCCCCHHHHHHHHHHHHHHHCCCCCEEEE
T ss_conf             3216777550785-56368267999999999863588705886