Conserved Protein Domain Family
ACT_RelA-SpoT

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cd04876: ACT_RelA-SpoT 
ACT domain found C-terminal of the RelA/SpoT domains
ACT_RelA-SpoT: the ACT domain found C-terminal of the RelA/SpoT domains. Enzymes of the Rel/Spo family enable bacteria to survive prolonged periods of nutrient limitation by controlling guanosine-3'-diphosphate-5'-(tri)diphosphate ((p)ppGpp) production and subsequent rRNA repression (stringent response). Both the synthesis of (p)ppGpp from ATP and GDP(GTP), and its hydrolysis to GDP(GTP) and pyrophosphate, are catalyzed by Rel/Spo proteins. In Escherichia coli and its close relatives, the metabolism of (p)ppGpp is governed by two homologous proteins, RelA and SpoT. The RelA protein catalyzes (p)ppGpp synthesis in a reaction requiring its binding to ribosomes bearing codon-specified uncharged tRNA. The major role of the SpoT protein is the breakdown of (p)ppGpp by a manganese-dependent (p)ppGpp pyrophosphohydrolase activity. Although the stringent response appears to be tightly regulated by these two enzymes in E. coli, a bifunctional Rel/Spo protein has been discovered in most gram-positive organisms studied so far. These bifunctional Rel/Spo homologs (rsh) appear to modulate (p)ppGpp levels through two distinct active sites that are controlled by a reciprocal regulatory mechanism ensuring inverse coupling of opposing activities. In studies with the Streptococcus equisimilis Rel/Spo homolog, the C-terminal domain appears to be involved in this reciprocal regulation of the two opposing catalytic activities present in the N-terminal domain, ensuring that both synthesis and degradation activities are not coinduced. Members of this CD belong to the superfamily of ACT regulatory domains.
Statistics
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PSSM-Id: 153148
View PSSM: cd04876
Aligned: 149 rows
Threshold Bit Score: 54.7637
Threshold Setting Gi: 34397606
Created: 1-Aug-2005
Updated: 2-Oct-2020
Structure
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Aligned Rows:
PubMed ReferencesClick to see Conserved Features Help

Sequence Alignment
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Format: Row Display: Color Bits: Type Selection:
NP_953285   643 IRVSCHDQKGILANITQAITd-cEANISSASIQStvdkRGVNIFEVDVTDldHLKRVMNNIMKLSGVISVER 713 Geobacter sulfurreducens...
NP_662429   659 IRIVGEDKIGMTNQITGVISk-fDTNIRTIVLNAkd-gIFTCNLMIFVKNtdKLTTLMDKLRKVQGVFTVER 728 Chlorobium tepidum TLS
ZP_00590896 660 IKVIGEDRIGITNQITAVISk-sDTNIRSISLHArd-gMFIGTVMVYVRNisRLTALMDKIRKITGVFSVER 729 Prosthecochloris aestuar...
YP_445194   673 LRLMGEDRVGMVNDITTVISknlKTNIRSITIDTed-gIFSGTIMLHVSDleHLQRLIERLKRIDGIQGVYR 743 Salinibacter ruber DSM 1...
AAQ66668    675 LHVIGQDNLAIVTNITSVINkepGVSLRAYSINSkd-nLFEGVFTVEVPDtsTLSILLRKIRATHGVKSAER 745 Porphyromonas gingivalis...
CAH07917    666 LRVVGHDDIGIVTNITSIISkenGISLRSIGIDSnd-gLFSGTLTIMVSDtgRLEALIKKLRTVKGVKQVSR 736 Bacteroides fragilis NCT...
YP_098049   674 IYIKGIDNVGLLNEITQVISrqlNVNIRKLDMETdd-gIFEGKVQLYVHDveDVKAICNNLRKIPNIKSVTR 744 Bacteroides fragilis YCH46
ZP_00533816 251 LDIKAADNIGFIQQISSIVTtefDVNIRSFNLKSte-gLIQLYMTVYIENteTLNKLIQRLRKIEEVIKITR 321 Chlorobium phaeobacteroi...
YP_000984   601 IEVKSKDRQGIFMEIVKSISn-tQTNIRESKASTdqrgNLVASFEVDVEHldQLKEILSNLKQIPDVYQAHR 671 Leptospira interrogans s...
6647734     686 LRVLTADRPGLLADITNTFSk-kGVNISQANCRAtgddRAVNTFEVIISDlkQLTDLMRTIERLQGVYSVER 756 Myxococcus xanthus
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