1AL3


Conserved Protein Domain Family
PBP2_CysB

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cd08443: PBP2_CysB 
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The C-terminal substrate domain of LysR-type transcriptional regulator CysB contains type 2 periplasmic binding fold.
CysB is a transcriptional activator of genes involved in sulfate and thiosulfate transport, sulfate reduction, and cysteine synthesis. In Escherichia coli, the regulation of transcription in response to sulfur source is attributed to two transcriptional regulators, CysB and Cbl. CysB, in association with Cbl, downregulates the expression of ssuEADCB operon which is required for the utilization of sulfur from aliphatic sulfonates, in the presence of cysteine. Also, Cbl and CysB together directly function as transcriptional activators of tauABCD genes, which are required for utilization of taurine as sulfur source for growth. Like many other members of the LTTR family, CysB 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: 176134
View PSSM: cd08443
Aligned: 4 rows
Threshold Bit Score: 359.569
Threshold Setting Gi: 1657422
Created: 16-Oct-2009
Updated: 2-Oct-2020
Structure
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Program:
Drawing:
Aligned Rows:
 
substrateputative
Conserved site includes 8 residues -Click on image for an interactive view with Cn3D
Feature 1:substrate binding site [chemical binding site]
Evidence:
  • Structure:1AL3_A; Klebsiella aerogenes CysB binds sulfuric acid, contacts at 4 A.
    View structure with Cn3D

Sequence Alignment
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Format: Row Display: Color Bits: Type Selection:
Feature 1           # ##                                            ###               #       
1AL3_A     94 SLYVATTHTQARYALPGVIKGFIERYPrVSLHMHQGSPTQIAEAVSKGnaDFAIATEAlhlyddLVMLPCYHWNRSIVVT 173 Klebsiella aerogenes
AAB17996   94 RIRLGATHTQARYVLPPVIRRFAAAYPaVELQIHQGTPGQLVDMALRDlvDLAICTEAlgdeiaLQTIPCYRWNRCLIAP 173 Thiocapsa roseoper...
EAY89955   56 SLYVATTHTQARYALPNVIKGFIERYPrVSLHMHQGSPTQIAEAVSKGtaDFAIATEAlhlyddLIMLPCYHWNRAVVVK 135 Indian rice
EEF80574   94 KLTIATTHTQARYVLPRTIIHFTNMHEsVGFQLKQGNPHQAFEMVSKGmvDFAIASEAmddfsnLITFPCYSWNRLVLVK 173 Methylophaga thioo...
Feature 1                                 #                                                   
1AL3_A    174 peHPLatkgsvsIEELAQYPLVTYtfgFTGRSELDTAFnragltpriVFTATDaDVIKTYVRLglGVGVIASMAVdpvsd 253 Klebsiella aerogenes
AAB17996  174 rsHAVldlqsitLAALCTVPIITYvfgFTGRGGFSDVFsraglhpnvVLSAADtDVIKTYVREglGVGIIAALAYqprdd 253 Thiocapsa roseoper...
EAY89955  136 pdHPLagkssisIEELAAYPIVTYtfgFTGRSELDTAFnragltpriVFTATDaDVIKTYVRLglGVGVIASMAVdpvqd 215 Indian rice
EEF80574  174 rdHPLasgapisIEQLSKYPLVTYengFTGRYQLNNAFqkaglepniMLTASDaDIIKAYVKMdlGVGVIASVAYdpddd 253 Methylophaga thioo...
Feature 1                                           
1AL3_A    254 pDLVKLdangIFSHSTTKIGFRRstFLRSYMYDFIQRF 291 Klebsiella aerogenes
AAB17996  254 aDLGIRdladLFPWEVTKIAYARgkYLRRFHEHFIDIF 291 Thiocapsa roseopersicina
EAY89955  216 pDLVTVdardIFTYSTTKIGFRRstFLRSYMYDFIQRF 253 Indian rice
EEF80574  254 cDLVSInvreLFDDCVAKIAIRKgvSLRSYMYDFIELF 291 Methylophaga thiooxidans DMS010

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