title: Conserved Ser residues, the shutter region, and speciation in serpin evolution.
abstract: The suicide inhibitory mechanism of serine protease inhibitors of the serpin superfamily depends heavily on their structural flexibility, which is controlled in large part by the breach and shutter regions of the central Abeta-sheet. We examined codon usage by the highly conserved residues, Ser-53 and Ser-56, of the shutter region and found a TCN-AGY usage dichotomy for Ser-56 that remarkably is linked to the protostome-deuterostome split. Our results suggest that serpin evolution was driven by phylogenetic speciation and not pressure to fulfill new physiologic functions mitigating against coevolution with the family of serine proteases they inhibit.
authors.affiliation: Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, Missouri 63110, USA.
authors.forename: Maxwell M
authors.initials: MM
authors.lastname: Krem
authors.forename: Enrico
authors.initials: E
authors.lastname: Di Cera
mesh_terms: D003062:Codon; D017124:Conserved Sequence; D010802:Phylogeny; D017510:Protein Folding; D012694:Serine; D015843:Serpins / Q000737:chemistry* / Q000235:genetics
chemical_list: D003062:Codon; D015843:Serpins; D012694:Serine