>TIGR02655 circ_KaiC circadian clock protein KaiC; InterPro: IPR013503 The circadian clock protein KaiC, is encoded in the kaiABC operon that controls circadian rhythms and may be universal in Cyanobacteria. Each member contains two copies of the KaiC domain, which is also found in other proteins. KaiC performs autophosphorylation and acts as its own transcriptional repressor. Kai proteins (KaiA and KaiC) appear to positively and negatively regulate kaiBC transcription which is consistent with a transcription/translation oscillatory (TTO) feedback model, believed to be at the core of all self-sustained circadian timers. However, the cyanobacterial circadian clock is able to function without de novo synthesis of clock gene mRNAs and the clock proteins, and the period is accurately determined without TTO feedback and the system is also temperature-compensated. It has been demonstrated that these three purified proteins form a temperature-compensated molecular oscillator in vitro that exhibits rhythmic phosphorylation and dephosphorylation of KaiC. A negative-stain electron microscopy study of Synechococcus elongatus and Thermosynechococcus elongatus BP-1 KaiAKaiC complexes in combination with site-directed mutagenesis reveals that KaiA binds exclusively to the CII half of the KaiC hexamer. The EM-based model of the KaiAKaiC complex reveals proteinprotein interactions at two sites: the known interaction of the flexible C-terminal KaiC peptide with KaiA, and a second postulated interaction between the apical region of KaiA and the ATP binding cleft on KaiC. This model brings KaiA mutation sites that alter clock period or abolish rhythmicity into contact with KaiC and suggests how KaiA might regulate KaiC phosphorylation . ; GO: 0000287 magnesium ion binding, 0003677 DNA binding, 0004674 protein serine/threonine kinase activity, 0005524 ATP binding, 0042752 regulation of circadian rhythm, 0045449 regulation of transcription.

Probab=98.00 E-value=0.00017 Score=47.98 Aligned_cols=148 Identities=26% Similarity=0.318 Sum_probs=112.9 Q ss_pred CCCCCCHHHHHHHCCCCCCCCCEEEEEECCCCHHHHHHHHHHHHHHHCCCEEEEEECCCCCCH--HHHHHHCCCHHH--- Q ss_conf 014772789997238972688079997068723789999998752008987999973885566--889981988334--- Q gi|255764460|r 47 VVSSGSLGLDIALGIGGFPKGRIVEIYGPESSGKTTLALHTIAQSQKTGGTCAFVDAEHALDS--IYARKLGVDLKN--- 121 (363) Q Consensus 47 ~i~TG~~~lD~~Lg~GG~p~Gri~ei~G~~~sGKTtlal~~~a~~qk~g~~~~~iD~E~~~~~--~~a~~~Gvd~~~--- 121 (363) T Consensus 244 rvssGv~~ld~mCG-GGff~dsiil~tGatGtGktllvs~f~~~~C~n~~railfayeesraql~rn~~sWG~dfe~~e~ 322 (484) T TIGR02655 244 RVSSGVKRLDEMCG-GGFFKDSIILATGATGTGKTLLVSKFLEDACKNKERAILFAYEESRAQLLRNAYSWGIDFEELEQ 322 (484) T ss_pred EEHHHHHHHHHHCC-CCEEEEEEEEEECCCCCCHHHHHHHHHHHHHCCCCCEEEEEEHHHHHHHHHCCCCCCCCHHHHCC T ss_conf 21000466643217-85121035676257776605566678886414677358885113467775233201443788500 Q ss_pred -----EEEEECC--CHHHHHHHHHHHHHCCCCCEEEEECCCCCCCHHHHHHHHHHHCCCHHHHHHHHHHHHHHHHHCCCC Q ss_conf -----4897258--489999999999744897689981433322026554345553022478887677677776420178 Q gi|255764460|r 122 -----LLISQPD--TGEQALEITDMLVRSGAVDIIVIDSVAALTPRAEIEGDMGESLPGMQARLMSQALRKLTSSISRSK 194 (363) Q Consensus 122 -----l~~~~~~--~~E~~~~i~~~li~~~~~~liViDSi~al~p~~Eie~~~~d~~~g~~ar~ms~~lrkl~~~~~k~~ 194 (363) T Consensus 323 ~~llki~C~yPes~Gledhlq~ik~~i~~fkP~r~~idslsala-r------------Gvs~nafrqfviGvtGyakqee 389 (484) T TIGR02655 323 QGLLKIICAYPESAGLEDHLQIIKSEIAEFKPARIAIDSLSALA-R------------GVSNNAFRQFVIGVTGYAKQEE 389 (484) T ss_pred CCCEEEEEECCCCCCHHHHHHHHHHHHHHCCCCHHHHHHHHHHH-H------------HHHHHHHEEEEEEECCCCCHHH T ss_conf 37237777077746617899999877742385300156577775-3------------2122100033564113112001 Q ss_pred CEEEEEECCCCCCC Q ss_conf 18999863411456 Q gi|255764460|r 195 CILVFINQMRMKIG 208 (363) Q Consensus 195 ~~~i~iNQ~r~~ig 208 (363) T Consensus 390 i~G~ftnt~~~f~G 403 (484) T TIGR02655 390 ITGFFTNTSDQFLG 403 (484) T ss_pred CEEEEECCHHHHCC T ss_conf 00222023012302

HHsearch alignment for GI: 255764460 and conserved domain: TIGR02655