Mar. Drugs 2012, 10(7), 1545-1565; doi:10.3390/md10071545
Article

Atypical Reactive Center Kunitz-Type Inhibitor from the Sea Anemone Heteractis crispa

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Received: 18 April 2012; in revised form: 4 July 2012 / Accepted: 11 July 2012 / Published: 19 July 2012
(This article belongs to the Special Issue Sea Anemone Toxins)
This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Abstract: The primary structure of a new Kunitz-type protease inhibitor InhVJ from the sea anemone Heteractis crispa (Radianthus macrodactylus) was determined by protein sequencing and cDNA cloning. InhVJ amino acid sequence was shown to share high sequence identity (up to 98%) with the other known Kunitz-type sea anemones sequences. It was determined that the P1 Thr at the reactive site resulted in a decrease of the Ki of InhVJ to trypsin and α-chymotrypsin (7.38 × 10−8 M and 9.93 × 10−7 M, respectively). By structure modeling the functional importance of amino acids at the reactive site as well as at the weak contact site were determined. The significant role of Glu45 for the orientation and stabilization of the InhVJ-trypsin complex was elucidated. We can suggest that there has been an adaptive evolution of the P1 residue at the inhibitor reactive site providing specialization or functional diversification of the paralogs. The appearance of a key so-called P1 Thr residue instead of Lys might lead to refinement of inhibitor specificity in the direction of subfamilies of serine proteases. The absence of Kv channel and TRPV1-receptor modulation activity was confirmed by electrophysiological screening tests.
Keywords: sea anemone; Kunitz-type protease inhibitor; structure; function; channels
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MDPI and ACS Style

Gladkikh, I.; Monastyrnaya, M.; Leychenko, E.; Zelepuga, E.; Chausova, V.; Isaeva, M.; Anastyuk, S.; Andreev, Y.; Peigneur, S.; Tytgat, J.; Kozlovkaya, E. Atypical Reactive Center Kunitz-Type Inhibitor from the Sea Anemone Heteractis crispa. Mar. Drugs 2012, 10, 1545-1565.

AMA Style

Gladkikh I, Monastyrnaya M, Leychenko E, Zelepuga E, Chausova V, Isaeva M, Anastyuk S, Andreev Y, Peigneur S, Tytgat J, Kozlovkaya E. Atypical Reactive Center Kunitz-Type Inhibitor from the Sea Anemone Heteractis crispa. Marine Drugs. 2012; 10(7):1545-1565.

Chicago/Turabian Style

Gladkikh, Irina; Monastyrnaya, Margarita; Leychenko, Elena; Zelepuga, Elena; Chausova, Victoria; Isaeva, Marina; Anastyuk, Stanislav; Andreev, Yaroslav; Peigneur, Steve; Tytgat, Jan; Kozlovkaya, Emma. 2012. "Atypical Reactive Center Kunitz-Type Inhibitor from the Sea Anemone Heteractis crispa." Mar. Drugs 10, no. 7: 1545-1565.


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