>TIGR02012 tigrfam_recA protein RecA; InterPro: IPR001553 The recA gene product is a multifunctional enzyme that plays a role in homologous recombination, DNA repair and induction of the SOS response . In homologous recombination, the protein functions as a DNA-dependent ATPase, promoting synapsis, heteroduplex formation and strand exchange between homologous DNAs . RecA also acts as a protease cofactor that promotes autodigestion of the lexA product and phage repressors. The proteolytic inactivation of the lexA repressor by an activated form of recA may cause a derepression of the 20 or so genes involved in the SOS response, which regulates DNA repair, induced mutagenesis, delayed cell division and prophage induction in response to DNA damage . RecA is a protein of about 350 amino-acid residues. Its sequence is very well conserved , , among eubacterial species. It is also found in the chloroplast of plants . RecA-like proteins are found in archaea and diverse eukaryotic organisms, like fission yeast, mouse or human. In the filament visualised by X-ray crystallography, ß-strand 3, the loop C-terminal to ß-strand 2, and alpha-helix D of the core domain form one surface that packs against alpha-helix A and ß-strand 0 (the N-terminal domain) of an adjacent monomer during polymerisation [Lusetti and Cox, Annu. Rev. Biochem. 2002. 71:71-100.]. The core ATP-binding site domain is well conserved, with 14 invariant residues. It contains the nucleotide binding loop between ß-strand 1 and alpha-helix C. The Escherichia coli sequence GPESSGKT matches the consensus sequence of amino acids (G/A)XXXXGK(T/S) for the Walker A box (also referred to as the P-loop) found in a number of nucleoside triphosphate (NTP)-binding proteins. Another nucleotide binding motif, the Walker B box is found at ß-strand 4 in the RecA structure. The Walker B box is characterised by four hydrophobic amino acids followed by an acidic residue (usually aspartate). Nucleotide specificity and additional ATP binding interactions are contributed by the amino acid residues at ß-strand 2 and the loop C-terminal to that strand, all of which are greater than 90

Probab=99.74 E-value=7.9e-17 Score=142.34 Aligned_cols=229 Identities=23% Similarity=0.347 Sum_probs=171.6 Q ss_pred CCCCCEECCCCCCCCCCCCCCCCHHHHHHHC-CCCCCCCEEEEECCCCCCHHHHHHHHHHHHHCCCCCEEEEECCCCHHH Q ss_conf 6656403133345566632378124888865-985787089995498751889999999998503981999986463047 Q gi|254780334|r 54 HSISLFMLSEESIEEESRIQTHIDELDRVTG-GGFVRGSVILVGGDPGIGKSTLLMQTAASLAYKKHRITYVSGEEAIGQ 132 (479) Q Consensus 54 ~~~~~~~l~~~~~~~~~Ri~TGi~eLDrvLG-GGl~~Gs~~Li~G~PGvGKSTL~Lqia~~~a~~g~~vlYvS~EEs~~Q 132 (479) T Consensus 18 GkG~im~Lg~~~~~~v~~i~tGsl~LD~AlG~GG~P~GRi~EiYGpESsGKTTLal~~iA~~Qk~Gg~~afiDAEHAlD~ 97 (322) T TIGR02012 18 GKGSIMKLGEKSVEDVEVISTGSLALDLALGVGGLPKGRIIEIYGPESSGKTTLALHVIAEAQKAGGVAAFIDAEHALDP 97 (322) T ss_pred CCCEEEECCCCCCCCEEEECCCCHHHHHHHCCCCCCCCEEEEEECCCCCCHHHHHHHHHHHHHHCCCEEEEEECHHHCCH T ss_conf 88214512554443100212530134355167989875079985489884789999999999743983899845130377 Q ss_pred HHHHHHHCCCCCCCHHEECCCCHH---HHHHHHHHCCCCCEEEECHHHHHHH-HHHCCCCCCH---HHHHHHHHHHHHH- Q ss_conf 888875201577510000347889---9999997316982899721687665-4204455636---7999999999997- Q gi|254780334|r 133 IRLRAQRLNTINSSVYIAIETNVE---DIIATLITNEKPDLVIIDSIQTLWS-QTAESSPGTV---IQVRTSVQAMIQY- 204 (479) Q Consensus 133 i~~Ra~Rl~~~~~~i~~~~e~~l~---~il~~~i~~~~~~~vVIDSIQtl~~-~~~~s~~Gsv---sQvre~~~~L~~~- 204 (479) T Consensus 98 --~YA~~LGv~~~~L~~sQPd~GE~ALeI~~~L~rSgAvD~iVvDSVAAL~P~aEieGemgd~~~Gl~ARLMS~ALRKl~ 175 (322) T TIGR02012 98 --VYAKKLGVDIDNLLVSQPDTGEQALEIAETLVRSGAVDIIVVDSVAALVPKAEIEGEMGDSHVGLQARLMSQALRKLT 175 (322) T ss_pred --HHHHHHCCCHHHHEEECCCCCHHHHHHHHHHHHCCCCEEEEECCCCCCCCHHHCCCCCCCCCCCHHHHHHHHHHHHHH T ss_conf --889983645247112088871469999999872376117997340013871231754354423257888999999888 Q ss_pred --HHHCCCEEEEEEEE-CCCCCCC-------CHHHHHHHHHEEE------EE-ECCCCCCCCCCEEEEEEEECCCC-CCC Q ss_conf --53079789998630-3665433-------1145787753027------85-15556665442156763202567-651 Q gi|254780334|r 205 --AKKNGVAMVLVGHV-TKEGQIA-------GPRVIEHMVDAVL------YF-EGGTRNTQYDYRILRSVKNRFGP-TDE 266 (479) Q Consensus 205 --AK~~~i~vilighv-TK~G~iA-------Gp~~LeH~VD~vl------~~-ege~~~~~~~~R~Lr~~KNRfG~-t~e 266 (479) T Consensus 176 g~~~k~~t~~iFiNQ~R~KiGv~fG~peTTtGG~ALKFYas~Rldirr~~~~K~g~~~~~G~~~-~vkv~KNKvApPF~~ 254 (322) T TIGR02012 176 GALSKSNTTLIFINQIREKIGVMFGNPETTTGGRALKFYASVRLDIRRIGSVKEGENEAVGNRV-KVKVVKNKVAPPFRE 254 (322) T ss_pred HHHHHCCCEEEEEEHHHHHCCCEECCCCCCCCCCHHHHHHHHHHHHHHHHHHHCCCHHHCCCEE-EEEEEEECCCCCHHH T ss_conf 7653205237640022223221117888877641423344334443114654154001014335-789875067985213 Q ss_pred EEEEEECCCCCEEECCHHH Q ss_conf 2799851566311014045 Q gi|254780334|r 267 IGVFEMSDKGLQEVSDPSK 285 (479) Q Consensus 267 ~gvf~m~~~Gl~~v~~ps~ 285 (479) T Consensus 255 aefdi~yg~Gi~~~g~~id 273 (322) T TIGR02012 255 AEFDILYGEGISKLGEIID 273 (322) T ss_pred HHEEEEECCCHHHHHHHHH T ss_conf 0010221114023345676

HHsearch alignment for GI: 254780334 and conserved domain: TIGR02012