2FYI


Conserved Protein Domain Family
PBP2_Cbl

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cd08444: PBP2_Cbl 
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The C-terminal substrate binding domain of LysR-type transcriptional regulator Cbl, which is required for expression of sulfate starvation-inducible (ssi) genes, contains the type 2 periplasmic binding fold.
Cbl is a member of the LysR transcriptional regulators that comprise the largest family of prokaryotic transcription factor. Cbl shows high sequence similarity to CysB, the LysR-type transcriptional activator of genes involved in sulfate and thiosulfate transport, sulfate reduction, and cysteine synthesis. In Escherichia coli, the function of Cbl is required for expression of sulfate starvation-inducible (ssi) genes, coupled with the biosynthesis of cysteine from the organic sulfur sources (sulfonates). The ssi genes include the ssuEADCB and tauABCD operons encoding uptake systems for organosulfur compounds, aliphatic sulfonates, and taurine. The genes in these operons encode an ABC-type transport system required for uptake of aliphatic sulfonates and a desulfonation enzyme. Both Cbl and CysB require expression of the tau and ssu genes. Like many other members of the LTTR family, the Cbl is composed of two functional domains joined by a linker helix involved in oligomerization: an N-terminal HTH (helix-turn-helix) domain, which is responsible for the DNA-binding specificity, and a C-terminal substrate-binding domain, which is structurally homologous to the type 2 periplasmic binding proteins. As also observed in the periplasmic binding proteins, the C-terminal domain of the bacterial transcriptional repressor undergoes a conformational change upon substrate binding which in turn changes the DNA binding affinity of the repressor. The structural topology of this substrate-binding domain is most similar to that of the type 2 periplasmic binding proteins (PBP2), which are responsible for the uptake of a variety of substrates such as phosphate, sulfate, polysaccharides, lysine/arginine/ornithine, and histidine. The PBP2 bind their ligand in the cleft between these domains in a manner resembling a Venus flytrap. After binding their specific ligand with high affinity, they can interact with a cognate membrane transport complex comprised of two integral membrane domains and two cytoplasmically located ATPase domains. This interaction triggers the ligand translocation across the cytoplasmic membrane energized by ATP hydrolysis.
Statistics
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PSSM-Id: 176135
View PSSM: cd08444
Aligned: 4 rows
Threshold Bit Score: 348.725
Threshold Setting Gi: 90109730
Created: 16-Oct-2009
Updated: 2-Oct-2020
Structure
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Program:
Drawing:
Aligned Rows:
 
putativedimerization
Conserved site includes 8 residues -Click on image for an interactive view with Cn3D
Feature 1:putative substrate binding site [chemical binding site]
Evidence:
  • Comment:based on sequence-structure similarity with Klebsiella aerogenes CysB (1AL3_A).

Sequence Alignment
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Format: Row Display: Color Bits: Type Selection:
Feature 1           # ##                                            ###               #       
2FYI_A     15 VLTIATTHTQARYSLPEVIKAFRELFPeVRLELIQGTPQEIATLLQNGeaDIGIASErlsndpqLVAFPWFRWHHSLLVP 94  Escherichia coli
EEV23674  107 ELSIATTHTQARYVLPWVVQRFKQQFPnVHLILHQADPESIANMVAQGqaDIGIATEsllahdnLHCIRYYDWYHHVIVP 186 Enhydrobacter aero...
NP_840656  94 ELTVATTHTQAQYALPDVVRQFKEIFPkVHLVLHESSPGEIVSMLLNGqaDIGIATEalestseLVSFPYYTWHHAIIVP 173 Nitrosomonas europ...
EET68241   94 EITIATTHTQARYALPGPIAAFRKEFPnVHLVLQQGSPKEIASMLNDGlaDIGIATEalenspeVVSFPYYSWHHGIIVP 173 Hyphomicrobium den...
Feature 1                                 #                                                   
2FYI_A     95 hdHPLtqispltLESIAKWPLITYrqgITGRSRIDDAFarkglladiVLSAQDsDVIKTYVALglGIGLVAEQSSgeqee 174 Escherichia coli
EEV23674  187 vgHELenrteidIQTLAKYPIITYhggFTGRGAIDRAFsaaeltpniVLTALDaDVISTYVGIgmGVGTIAEMAFegqhy 266 Enhydrobacter aero...
NP_840656 174 aeHPLqsihpltLEAVAQFPIITYhkgFTGRSRIDQAFsraeltpniAMSALDaDVIKTYVTLgmGIGIVASVAFtperd 253 Nitrosomonas europ...
EET68241  174 kgHALesvkpltIEKIAEWPIITYhegFTGRPGVDATFakagltpdiVMVALDaDVIKTYVEVglGIGIVASMAYdkdrd 253 Hyphomicrobium den...
Feature 1                                           
2FYI_A    175 eNLIRLdtrhLFDANTVWLGLKRgqLQRNYVWRFLELC 212 Escherichia coli
EEV23674  267 rNLVKIpt-kIFGKHVTWIATRVdgDIRNFGKAFIDIC 303 Enhydrobacter aerosaccus SK60
NP_840656 254 tKLIKLdgshLFEQNTTCISIRRnhYLRGYAYRFIELC 291 Nitrosomonas europaea ATCC 19718
EET68241  254 tGLRLLdnshLFPKTTTRIALRRgrFLRRFAYRFIELC 291 Hyphomicrobium denitrificans ATCC 51888

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