Structural requirements for processing of pro-adipokinetic hormone I.
We found that a seven-residue sequence in pro-adipokinetic hormone I (proAKH I) which precedes the endopeptidase cleavage site is predicted to form an omega loop. Molecular modelling experiments indicated that a stable omega loop may form at this site, and suggested that loop stability may depend on the C-terminal loop residue, Lys12. The importance of this residue in proAKH I processing was confirmed by the observation that replacement of Lys12 by thialysine, a Lys analog with an altered side chain, prevented processing in vivo. In addition we showed by molecular modelling that this side-chain alteration may prevent formation of an omega loop. Together, these approaches lead us to propose that an omega loop may serve as a recognition motif in proAKH I processing.
Rayne
R C
RC
Sussex Centre for Neuroscience, School of Biological Sciences, University of Sussex, Brighton, England.
O'Shea
M
M
D000595:Amino Acid Sequence; D000818:Animals; D001665:Binding Sites; D010450:Endopeptidases / Q000378:metabolism; D006110:Grasshoppers; D007301:Insect Hormones / Q000737:chemistry / Q000378:metabolism*; D008958:Models, Molecular; D008969:Molecular Sequence Data; D011498:Protein Precursors / Q000737:chemistry / Q000378:metabolism; D011499:Protein Processing, Post-Translational; D017433:Protein Structure, Secondary; D017386:Sequence Homology, Amino Acid
D007301:Insect Hormones; D011498:Protein Precursors; C014956:adipokinetic hormone (locust); D010450:Endopeptidases