Primary Citation of Related Structures: 1AS4, 3CAA, 4CAA
PubMed Abstract:
Expressed in a kinetically trapped folding state, a serpin couples the thermodynamic driving force of a massive beta-sheet rearrangement to the inhibition of a target protease. Hence, the serpin-protease interaction is the premier example of a "spring-loaded" protein-protein interaction ...
Expressed in a kinetically trapped folding state, a serpin couples the thermodynamic driving force of a massive beta-sheet rearrangement to the inhibition of a target protease. Hence, the serpin-protease interaction is the premier example of a "spring-loaded" protein-protein interaction. Amino acid substitutions in the hinge region of a serpin reactive loop can weaken the molecular spring, which converts the serpin from an inhibitor into a substrate. To probe the molecular basis of this conversion, we report the crystal structure of A349R antichymotrypsin in the reactive loop cleaved state at 2.1 A resolution. This amino acid substitution does not block the beta-sheet rearrangement despite the burial of R349 in the hydrophobic core of the cleaved serpin along with a salt-linked acetate ion. The inhibitory activity of this serpin variant is not obliterated; remarkably, its inhibitory properties are anion-dependent due to the creation of an anion-binding cavity in the cleaved serpin.
Related Citations:
Arginine Substitutions in the Hinge Region of Antichymotrypsin Affect Serpin Beta-Sheet Rearrangement Lukacs, C.M., Zhong, J.Q., Plotnick, M.I., Rubin, H., Cooperman, B.S., Christianson, D.W. (1996) Nat Struct Biol 3: 888
Organizational Affiliation:
Department of Chemistry, University of Pennsylvania, Philadelphia 19104, USA.
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