>TIGR00259 TIGR00259 conserved hypothetical protein TIGR00259; InterPro: IPR005137 Photosystem I (PSI) is a large protein complex embedded within the photosynthetic thylakoid membrane. It consists of 11 subunits, ~100 chlorophyll a molecules, 2 phylloquinones, and 3 Fe4S4-clusters. The three dimensional structure of the PSI complex has been resolved at 2.5 A , which allows the precise localisation of each cofactor. PSI together with photosystem II (PSII) catalyses the light-induced steps in oxygenic photosynthesis - a process found in cyanobacteria, eukaryotic algae (e.g. red algae, green algae) and higher plants. To date, three thylakoid proteins involved in the stable accumulation of PSI have been identified: BtpA , Ycf3 , , and Ycf4 (IPR003359 from INTERPRO) . Because translation of the psaA and psaB mRNAs encoding the two reaction centre polypeptides, of PSI and PSII respectively, is not affected in mutant strains lacking functional ycf3 and ycf4, the products of these two genes appear to act at a post-translational step of PSI biosynthesis. These gene products are therefore involved either in the stabilisation or in the assembly of the PSI complex. However, their exact roles remain unknown. The BtpA protein appears to act at the level of PSI stabilisation . It is an extrinsic membrane protein located on the cytoplasmic side of the thylakoid membrane , . Homologs of BtpA are found in the crenarchaeota and euryarchaeota, where their function remains unknown. The Ycf4 protein is firmly associated with the thylakoid membrane, presumably through a transmembrane domain . Ycf4 co-fractionates with a protein complex larger than PSI upon sucrose density gradient centrifugation of solubilised thylakoids . The Ycf3 protein is loosely associated with the thylakoid membrane and can be released from the membrane with sodium carbonate. This suggests that Ycf3 is not part of a stable complex and that it probably interacts transiently with its partners . Ycf3 contains a number of tetratrico peptide repeats (TPR, IPR001440 from INTERPRO); TPR is a structural motif present in a wide range of proteins, which mediates proteinprotein interactions. .

Probab=94.30 E-value=0.46 Score=26.94 Aligned_cols=224 Identities=17% Similarity=0.253 Sum_probs=124.0 Q ss_pred CEEECCCCCCCHHHHHHHHHCCCCEEECCCCCCCCCCCCCCCCEEEEECCCCCEEECCCCCCCHHHHHHHHHHHHHCCCC Q ss_conf 74853468886779888740367524102001368789988626884255541000024777778899987641000121 Q gi|254780434|r 57 PLGMAAGYDKNAEVPIELLKLGFGFVEIGTVTPHPQAGNPRPRVFRLTKDRAIINKLGFNNAGYHTVFSRLSKIQPTSPI 136 (362) Q Consensus 57 PiglAaG~dk~~~~~~~l~~~G~G~v~~ktit~~p~~GNp~PR~~r~~~~~~iiN~~Gl~N~G~~~~~~~l~~~~~~~pi 136 (362) T Consensus 22 ~lGl~~vid~A~~da~aL~~GG~DAv~~eN~fd~P---F~kq~v-----~~~tvAAM-------a~I~~~l~~-~v~~Pl 85 (261) T TIGR00259 22 NLGLNAVIDKAVKDAKALEEGGVDAVILENFFDAP---FLKQEV-----DPETVAAM-------AVIAKELKE-DVSIPL 85 (261) T ss_pred CCCHHHHHHHHHHHHHHHHHCCCCEEEEECCCCCC---CCCCCC-----CHHHHHHH-------HHHHHHHHH-CCCCCC T ss_conf 55648999999999999985698789985246869---776505-----63443188-------999998875-120464 Q ss_pred CCEEECCCCCHHHHH--HHHHHHHHHCCCCCEEEEECCCCCCCCCCCCCCHHHHHHHHHHHHHHHHHHHHHCCCCCEEE- Q ss_conf 000110454246788--77655542067552698303336532211000023432111122444556553126885178- Q gi|254780434|r 137 GINLGANKDSKDFIL--DYVSGIRLFFTIASYFTINISSPNTPGLRSLQKKKNLERLLIHVMQTREEEKIKTGKFVPIF- 213 (362) Q Consensus 137 ~vsI~~~~~s~~~~~--dy~~~~~~~~~~aD~iEiNiSCPNt~g~~~~~~~~~l~~~l~~v~~~~~~~~~~~~~~~Pi~- 213 (362) T Consensus 86 GiNvLrN----Da~aa~~iA~~-----v~A~FiRVn~L~G~-----~~sD~G~~eg~a~E~~ry~~~--~~s-G~v~~la 148 (261) T TIGR00259 86 GINVLRN----DAVAALAIAKA-----VGAKFIRVNVLTGV-----AASDQGIIEGNAGELLRYKKL--LGS-GEVKILA 148 (261) T ss_pred CEEEECC----CHHHHHHHHHH-----HCCCEEEEEEEEEE-----EECCCCCEECCHHHHHHHHHC--CCC-CCEEEEE T ss_conf 1012123----47778988676-----47726898533212-----553674000416543343312--676-6456303 Q ss_pred ---EECCCCCCHHHHHHHHHH-HHHCCCCEEEEECCCCCCCCCCCCCCCCCCCCCCCCCCCHHHHHHHHHHHHHCCCCEE Q ss_conf ---650577774888999998-7644982999806655532345775446322113564542468999999974089748 Q gi|254780434|r 214 ---LKISPDLSEEELDDIAVE-VLSHKVEGIIVSNTTLSRKGVQCSDNHEQDGGLSGSPLFLKSTIALAKIRQRVGPKIA 289 (362) Q Consensus 214 ---vKLsPd~~~~~i~~ia~~-a~~~g~dGiv~~NT~~~~~~~~~~~~~~~~GGlSG~~i~~~al~~i~~i~~~~~~~i~ 289 (362) T Consensus 149 dv~vkhA~~lG~~~l~~~~~~Tver~laDAvi~SG~~------------------tG---~~~~~e~Lk~ak~~~~-~~p 206 (261) T TIGR00259 149 DVVVKHAVHLGNRDLESIVLDTVERGLADAVILSGKT------------------TG---TEVDLEELKLAKETVK-DTP 206 (261) T ss_pred CCCHHHCCCCCCCCHHHHHHHHHHHCCCCEEEEECCC------------------CC---CCCCHHHHHHHHHHCC-CCE T ss_conf 1524521025883668898644541698838981545------------------78---8878888999987517-966 Q ss_pred EEEECCCCCHHHHHHHHHCCCCEEEECHHHHCCC-------HHHHHHHHHHHHHH Q ss_conf 9996788999999999983999754527877069-------78999999999999 Q gi|254780434|r 290 IIGTGGISSTKDALDKIMAGANLIQLYSAMIYEG-------ISLPKRIIQGLSDF 337 (362) Q Consensus 290 IIg~GGI~s~~Da~e~l~aGAs~VQi~Tali~~G-------p~~~~~I~~~L~~~ 337 (362) T Consensus 207 Vl~gsG~~~--~N~~~ll~~AdG~ivat~~Kk~G~~nn~vD~~Rv~~~~~~~a~~ 259 (261) T TIGR00259 207 VLAGSGVNL--ENVEELLSIADGVIVATTIKKDGKINNLVDQERVSKFVEKVAEG 259 (261) T ss_pred EEEECCCCH--HHHHHHHHHHCCEEEEEEEECCCCCCHHHHHHHHHHHHHHHHHH T ss_conf 998478798--89999998739879835653388420042189999999999852

HHsearch alignment for GI: 254780434 and conserved domain: TIGR00259