Structural requirements of KTS-disintegrins for inhibition of α1β1 integrin

Abstract

Obtustatin and viperistatin represent the shortest known snake venom monomeric disintegrins. In the present study, we have produced recombinant full-length wild-type and site-directed mutants of obtustatin to assess the role of the K(21)TS(23) tripeptide and C-terminal residues for specific inhibition of the alpha(1)beta(1) integrin. Thr(22) appeared to be the most critical residue for disintegrin activity, whereas substitution of the flanking lysine or serine residues for alanine resulted in a less pronounced decrease in the anti-alpha(1)beta(1) integrin activity of the disintegrin. The triple mutant A(21)AA(23) was devoid of blocking activity towards alpha(1)beta(1) integrin-mediated cell adhesion. The potency of recombinant KTS-disintegrins also depended on the residue C-terminally adjacent to the active motif. Substitution of Leu(24) of wild-type obtustatin for an alanine residue slightly decreased the inhibitory activity of the mutant, whereas an arginine residue in this position enhanced the potency of the mutant over wild-type obtustatin by 6-fold. In addition, the replacements L38V and P40Q may account for a further 25-fold increase in alpha(1)beta(1) inhibitory potency of viperistatin over KTSR-obtustatin.

Metalloproteases Affecting Blood Coagulation, Fibrinolysis and Platelet Aggregation from Snake Venoms: Definition and Nomenclature of Interaction Sites

“…When their second subunit contains RGD, they bind to α 5 β 1 integrin [184]. Disintegrins with KTS/RTS motif bind to α 1 β 1 integrin [135,185,186,187,188,189]. The selectivity and potency strongly depends on the amino acid composition surrounding RGD/MLD/KTS/RTS motifs.…”

Isolation and characterization of four medium-size disintegrins from the venoms of Central American viperid snakes of the genera Atropoides, Bothrops, Cerrophidion and Crotalus

“…The threonine present in the tripeptide KTS of the disintegrin obtustatin is key for the binding to a 1 b 1 integrin [40]. It has been suggested that the RTS/KTS short disintegrins may have been recruited into the venom gland of Eurasian vipers independently of the canonical neofunctionalization pathway characteristic of the RGD disintegrins [41].…”

NMRstructure of bitistatin – a missing piece in the evolutionary pathway of snake venom disintegrins

“…Dimeric disintegrins exhibit the largest variability in their integrin recognition motifs, including MLD (in addition to RGD and KGD), which targets the a 4 b 1 , a 4 b 7 , a 3 b 1 , a 6 b 1 , a 7 b 1 and a 9 b 1 integrins; VGD and MGD, which impair the function of the a 5 b 1 integrin; and WGD, a potent inhibitor of the RGD-dependent integrins a 5 b 1 , a v b 3 , and a IIb b 3 [25,26]. KTS and RTS motifs have been found in short disintegrins, which selectively target the integrin a 1 b 1 [29,30] and form a distinct clade of recently evolved short disintegrins [31].…”