HBM helical bimodular (HBM) domain
SMART ACC:	SM001358
Description:	The HBM domain was identified in Bacteria and Archaea and forms part of chemoreceptors and histidine kinases. The domain was characterized by a bimodular architecture, where ligand binding to each module caused a chemotactic response. The conservation of amino acids in the ligand binding sites of both modules suggests that HBM family members recognize similar ligands. (PMID:24347303)
InterPro ACC:	IPR032255
InterPro abstract:	The HBM sensor domain has been identified primarily in bacterial chemoreceptors but is also present on histidine kinases. Characteristic features of this domain are its size of approximately 250 amino acids and its location in the bacterial periplasm [ PUBMED:20498372 ]. The McpS chemoreceptor of Pseudomonas putida KT2440 … expand The HBM sensor domain has been identified primarily in bacterial chemoreceptors but is also present on histidine kinases. Characteristic features of this domain are its size of approximately 250 amino acids and its location in the bacterial periplasm [ PUBMED:20498372 ]. The McpS chemoreceptor of Pseudomonas putida KT2440 was found to possess an HBM sensor domain and its 3D structure in complex with physiologically relevant ligands has been reported [ PUBMED:21360620 ]. This domain is composed of 2 long and 4 short helices that form two modules each composed of a 4-helix bundle. The McpS chemoreceptor mediates chemotaxis towards a number of organic acids [ PUBMED:20498372 PUBMED:23112148 ]. Both modules of the McpS HBM domain contain a ligand binding site. Chemo-attractants binds to each of these sites and their binding was shown to trigger a chemotactic response [ PUBMED:24347303 ]. This domain is primarily found in different proteobacteria but also in archaea. Interestingly, amino acids in both ligand binding sites showed a high degree of conservation suggesting that members of this family sense similar ligands. collapse
Family alignment:	View the Family alignment or the Alignment consensus sequence
There are 6 237 HBM domains in 6 223 proteins in SMART's NRDB database.

Taxonomic distribution of proteins containing HBM domains

The tree below includes only several representative species and genera. The complete taxonomic breakdown of all proteins containing HBM domains can be accessed here. Click the counts or percentage values to display the corresponding proteins.

Relevant references for this domain

Primary literature for the HBM domain is listed below. Automatically-derived, secondary literature is also available.

KEGG pathways involving proteins which contain this domain

This information is based on the mapping of SMART genomic protein database to KEGG orthologous groups. Percentages are related to the number of proteins containing a HBM domain which could be assigned to a KEGG orthologous group, and not all proteins containing HBM domains. Please note that proteins can be included in multiple pathways, ie. the numbers below will not add to 100%.

KEGG pathways

KEGG orthologous groups

3D structures in PDB containing this domain

Links to other resources describing this domain

InterPro	IPR032255