pubmed-article:8223647 | pubmed:abstractText | 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. | lld:pubmed |