PROSITE documentation PDOC51753HBM domain profile
The helical bimodular (HBM) domain is a small molecule binding domain of around 250 amino acids. It is found in Bacteria and Archaea but is absent from eukaryotes and forms part of chemoreceptors (see <PDOC00465>) and histidine kinases (see <PDOC50109>). The HBM domain is composed of two structural modules, each of which recognizes a different type of ligand. The conservation of amino acids in the ligand binding sites of both modules suggests that HBM family members recognize similar ligands [1].
The HBM domain is composed of six helices linked by loops (see <PDB:2YFB>). Two short helices (α1 and α2) at the membrane-proximal part of the structure are followed by the long helix α3. This segment is followed by another couple of short helices (α4 and α5) and a second long helix α6, which is predicted to continue as a transmembrane helix. The structure can be understood as a duplication of a structural element made of two short and a long helix. The six helices of the HBM domain arrange into two modules, each forming a four-helix bundle. The membrane proximal module is composed of α1, α2, the N-terminal segment of α 3, and the C-terminal segment of α6. The membrane distal module is composed of the C-terminal segment of α3, helices α4 and α5, and the the N-terminal part of α6 [2].
The profile we developed covers the entire HBM domain.
Last update:April 2015 / First entry.
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PROSITE method (with tools and information) covered by this documentation:
| 1 | Authors | Ortega A. Krell T. |
| Title | The HBM domain: introducing bimodularity to bacterial sensing. | |
| Source | Protein Sci. 23:332-336(2014). | |
| PubMed ID | 24347303 | |
| DOI | 10.1002/pro.2410 |
| 2 | Authors | Pineda-Molina E. Reyes-Darias J.-A. Lacal J. Ramos J.L. Garcia-Ruiz J.M. Gavira J.A. Krell T. |
| Title | Evidence for chemoreceptors with bimodular ligand-binding regions harboring two signal-binding sites. | |
| Source | Proc. Natl. Acad. Sci. U.S.A. 109:18926-18931(2012). | |
| PubMed ID | 23112148 | |
| DOI | 10.1073/pnas.1201400109 |
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