Editor-in-Chief: Brüne, Bernhard
Editorial Board: Buchner, Johannes / Lei, Ming / Ludwig, Stephan / Sies, Helmut / Thomas, Douglas D. / Turk, Boris / Wittinghofer, Alfred
12 Issues per year
IMPACT FACTOR 2016: 3.273
CiteScore 2016: 3.01
SCImago Journal Rank (SJR) 2016: 1.679
Source Normalized Impact per Paper (SNIP) 2016: 0.800
Trypsin inhibition by macrocyclic and open-chain variants of the squash inhibitor MCoTI-II
MCoTI-I and MCoTI-II from the seeds of Momordica cochinchinensis are inhibitors of trypsin-like proteases and the only known members of the large family of squash inhibitors that are cyclic and contain an additional loop connecting the amino- and the carboxy-terminus. To investigate the contribution of macrocycle formation to biological activity, we synthesized a set of open-chain variants of MCoTI-II that lack the cyclization loop and contain various natural and non-natural amino acid substitutions in the reactive-site loop. Upon replacement of P1 lysine residue #10 within the open-chain variant of MCoTI-II by the non-natural isosteric nucleo amino acid AlaG [β-(guanin-9-yl)-L-alanine], a conformationally restricted arginine mimetic, residual inhibitory activity was detected, albeit reduced by four orders of magnitude. While the cyclic inhibitors MCoTI-I and MCoTI-II were found to be very potent trypsin inhibitors, with picomolar inhibition constants, the open-chain variants displayed an approximately 10-fold lower affinity. These data suggest that the formation of a circular backbone in the MCoTI squash inhibitors results in enhanced affinity and therefore is a determinant of biological activity.
Here you can find all Crossref-listed publications in which this article is cited. If you would like to receive automatic email messages as soon as this article is cited in other publications, simply activate the “Citation Alert” on the top of this page.