Structural basis for differences in substrate selectivity in Kex2 and furin protein convertases.
Kex2 is the yeast prototype of a large family of serine proteases that are highly specific for cleavage of their peptide substrates C-terminal to paired basic sites. This paper reports the 2.2 A resolution crystal structure of ssKex2 in complex with an Ac-Arg-Glu-Lys-Arg peptidyl boronic acid inhibitor (R = 19.7, R(free) = 23.4). By comparison of this structure with the structure of the mammalian homologue furin [Henrich, S., et al. (2003) Nat. Struct. Biol. 10, 520-526], we suggest a structural basis for the differences in substrate recognition at the P(2) and P(4) positions between Kex2 and furin and provide a structural rationale for the lack of P(6) recognition in Kex2. In addition, several monovalent cation binding sites are identified, and a mechanism of activation of Kex2 by potassium ion is proposed.
Holyoak
Todd
T
Rosenstiel Basic Medical Sciences Research Center, Brandeis University, Waltham, Massachusetts 02454, USA.
Kettner
Charles A
CA
Petsko
Gregory A
GA
Fuller
Robert S
RS
Ringe
Dagmar
D
D001665:Binding Sites; D001897:Boronic Acids / Q000737:chemistry / Q000378:metabolism; D018360:Crystallography, X-Ray; D045683:Furin / Q000037:antagonists & inhibitors / Q000737:chemistry* / Q000378:metabolism; D009842:Oligopeptides / Q000737:chemistry / Q000378:metabolism; D043484:Proprotein Convertases / Q000037:antagonists & inhibitors / Q000737:chemistry* / Q000378:metabolism; D011485:Protein Binding; D029701:Saccharomyces cerevisiae Proteins / Q000037:antagonists & inhibitors / Q000737:chemistry* / Q000378:metabolism; D013329:Structure-Activity Relationship; D013379:Substrate Specificity
D001897:Boronic Acids; D009842:Oligopeptides; D029701:Saccharomyces cerevisiae Proteins; D043484:Proprotein Convertases; C058751:KEX2 protein, S cerevisiae; D045683:Furin