HHsearch alignment for GI: 254781111 and conserved domain: cd00683
>cd00683 Trans_IPPS_HH Trans-Isoprenyl Diphosphate Synthases (Trans_IPPS), head-to-head (HH) (1'-1) condensation reaction. This CD includes squalene and phytoene synthases which catalyze the 1'-1 condensation of two 15-carbon (farnesyl) and 20-carbon (geranylgeranyl) isoprenyl diphosphates, respectively. The catalytic site consists of a large central cavity formed by mostly antiparallel alpha helices with two aspartate-rich regions (DXXXD) located on opposite walls. These residues mediate binding of prenyl phosphates. A two-step reaction has been proposed for squalene synthase (farnesyl-diphosphate farnesyltransferase) in which, two molecules of FPP react to form a stable cyclopropylcarbinyl diphosphate intermediate, and then the intermediate undergoes heterolysis, isomerization, and reduction with NADPH to form squalene, a precursor of cholestrol. The carotenoid biosynthesis enzyme, phytoene synthase (CrtB), catalyzes the condensation reaction of two molecules of geranylgeranyl diphosp
Probab=94.03 E-value=0.25 Score=27.09 Aligned_cols=73 Identities=19% Similarity=0.188 Sum_probs=48.1
Q ss_pred HHHHCCCCCCCCHHH-HHHHHHHHHHHHHHHHHHHHHHHHHHHHCCCCHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHC
Q ss_conf 664113322210000-0036799999998634899999999997598889999999999998499999867653443206
Q gi|254781111|r 157 QGMLGGQMLDIQDEF-IDETQVFMIQKMKTGALMCFACESGAIMAHASQNEKERLRCFGENLGIIFQLADDLLDCEEDLP 235 (237)
Q Consensus 157 ~~l~~GQ~~dl~~~~-~~~~~y~~i~~~KTa~lf~~~~~~ga~lag~~~~~~~~l~~~g~~lGiafQi~DD~lD~~~D~~ 235 (237)
T Consensus 96 ~~li~g~~~Dl~~~~~~t~~eL~~Yc~~vAg~VG~l~~~i---~g~~~---~~~~~~~A~~lG~AlQltNilRDi~eD~~ 169 (265)
T cd00683 96 RDLLAGMAMDLDKRRYETLDELDEYCYYVAGVVGLMLLRV---FGASS---DEAALERARALGLALQLTNILRDVGEDAR 169 (265)
T ss_pred HHHHHHHHHHCCCCCCCCHHHHHHHHHHHHHHHHHHHHHH---HCCCC---HHHHHHHHHHHHHHHHHHHHHHHHHHHHH
T ss_conf 9999999987567899999999999997117999999999---58788---18899999998899999989987999995