1K68

Crystal Structure of the Phosphorylated Cyanobacterial Phytochrome Response Regulator RcpA

Summary for 1K68

• Entry DOI: 10.2210/pdb1k68/pdb
• Related: 1K66
• Descriptor: Phytochrome Response Regulator RcpA, MAGNESIUM ION (3 entities in total)
• Functional Keywords: phosphorylated aspartate, response regulator, chey homologue, homodimer, (beta/alpha)5, signaling protein
• Biological source: Tolypothrix sp. PCC 7601
• Total number of polymer chains: 2
• Total formula weight: 31772.57

Authors

Benda, C.,Scheufler, C.,Tandeau de Marsac, N.,Gaertner, W. (deposition date: 2001-10-15, release date: 2003-12-16, Last modification date: 2025-03-26)

Primary citation

Benda, C.,Scheufler, C.,Tandeau de Marsac, N.,Gaertner, W.
Crystal structures of two cyanobacterial response regulators in apo- and phosphorylated form reveal a novel dimerization motif of phytochrome-associated response regulators
Biophys.J., 87:476-487, 2004

PubMed Abstract: The structures of two response regulators (RRs) from the cyanobacterium Calothrix PCC7601, RcpA and RcpB, were solved to 1.9- and 1.75-A resolution, respectively. RcpA was found in phosphorylated and RcpB in nonphosphorylated form. Both RRs are members of phytochrome-associated, light-sensing two-component signal transduction pathways, based on histidine kinase-mediated receptor autophosphorylation and phosphorelay to a RR. Despite the overall folding similarity to CheY-type RRs ((beta/alpha)(5)-motif), RcpA and RcpB form homodimers, irrespective of their phosphorylation state, giving insight into a signal transduction putatively different from that of other known RRs. Dimerization is accomplished by a C-terminal extension of the RR polypeptide chain, and the surface formed by H4, beta 5, and H5, which constitute a hydrophobic contact area with distinct interactions between residues of either subunit. Sequence alignments reveal that the identified dimerization motif is archetypal for phytochrome-associated RRs, making them a novel subgroup of CheY-type RRs. The protein structures of RcpA and RcpB are compared to the recently presented protein structure of Rcp1 from Synechocystis.

PubMed: 15240481
DOI: 10.1529/biophysj.103.033696

Experimental method

X-RAY DIFFRACTION (1.9 Å)