Disulfide linkages and a three-dimensional structure model of the extracellular ligand-binding domain of guanylyl cyclase C.
Guanylyl cyclase C (GC-C) is a single-transmembrane receptor that is specifically activated by endogenous ligands, including guanylin, and the exogenous ligand, heat-stable enterotoxin. Using combined HPLC separation and MS analysis techniques the positions of the disulfide linkages in the extracellular ligand-binding domain (ECD) of GC-C were determined to be between Cys7-Cys94, Cys72-Cys77, Cys101-Cys128 and Cys179-Cys226. Furthermore, a three-dimensional structural model of the ECD was constructed by homology modeling, using the structure of the ECD of GC-A as a template (van den Akker et al., 2000, Nature, 406: 101-104) and the information of the disulfide linkages. Although the GC-C model was similar to the known structure of GC-A, importantly its ligand-binding site appears to be located on the quite different region from that in GC-A.
Hasegawa
Makoto
M
Faculty of Bioscience, Nagahama Institute of Bio-Science and Technology, Nagahama, Shiga, 526-0829, Japan. m_hasegawa@nagahama-i-bio.ac.jp
Matsumoto-Ishikawa
Yoshiko
Y
Hijikata
Atsushi
A
Hidaka
Yuji
Y
Go
Mitiko
M
Shimonishi
Yasutsugu
Y
D000595:Amino Acid Sequence; D001665:Binding Sites; D003488:Cyanogen Bromide / Q000494:pharmacology; D004220:Disulfides / Q000737:chemistry; D006162:Guanylate Cyclase / Q000737:chemistry* / Q000235:genetics*; D008024:Ligands; D008958:Models, Molecular; D008969:Molecular Sequence Data; D010449:Peptide Mapping; D017434:Protein Structure, Tertiary; D000074261:Receptors, Enterotoxin; D050705:Receptors, Guanylate Cyclase-Coupled; D018000:Receptors, Peptide / Q000737:chemistry* / Q000235:genetics*; D017386:Sequence Homology, Amino Acid
D004220:Disulfides; D008024:Ligands; D018000:Receptors, Peptide; D006162:Guanylate Cyclase; D000074261:Receptors, Enterotoxin; D050705:Receptors, Guanylate Cyclase-Coupled; D003488:Cyanogen Bromide