The HAMP linker domain (domain present in Histidine kinases, Adenyl cyclases,
Methyl-accepting proteins and Phosphatases) is an approximately 50-amino acid
α-helical region common to chemoreceptors and histidine kinases that is
present in several multidomain sensor proteins that participate in a variety
of signal transduction processes. One or several copies of the HAMP domain can
be found in association with other domains such as the histidine kinase domain
(see <PDOC50109>), the bacterial chemotaxis sensory transducer domain (see
<PDOC00465>), the PAS repeat (see <PDOC50112>), the EAL domain (see
<PDOC50883>), the GGDEF domain (see <PDOC50887>), the protein phosphatase 2C-like domain, the guanylate cyclase domain (see <PDOC00425>), or the response
regulatory domain (see <PDOC50110>). It has been suggested that the HAMP
domain possesses a role of regulating the phosphorylation or methylation of
homodimeric receptors by transmitting the conformational changes in
periplasmic ligand-binding domains to cytoplasmic signalling kinase and
methyl-acceptor domains .
Some proteins known to contain a HAMP domain are listed below:
Anabaena cylindrica adenylate cyclase. It may function as a membrane-
localized receptor protein.
Escherichia coli osmolarity sensor protein envZ. It functions as a
membrane-associated protein kinase that phosphorylates ompR in response to
Escherichia coli sensor protein barA. It could activate ompR by
Escherichia coli nitrate/nitrite sensor protein narX. It probably activates
narL and narP by phosphorylation in the presence of nitrate.
Escherichia coli sensor protein cpxA.
Escherichia coli methyl-accepting chemotaxis protein I.
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