%0 Journal Article
%T Roles of lysine-69 in dimerization and activity of Trimeresurus flavoviridis venom aspartate-49-phospholipase A2
%J Journal of Molecular Recognition
%D 1996
%A Nakamura, S.
%A Nakai, M.
%A Nakashima, K.
%A Ogawa, Toshiki
%A Shimohigashi, Y.
%A Ohno, M.
%A Kihara, H.
%A Yamane, T.
%A Ashida, T.
%V 9
%N 1
%P 23-30
%X Trimeresurus flavoviridis (Habu snake) venom aspartate-49-phospholipase A2 (Asp-49-PLA2) was reacted at pH 9.0 with a 2-fold molar excess of 2,4,6-trinitrobenzenesulfonate in the absence of Ca2+ and two trinitrophenylated derivatives were isolated by HPLC. One was a derivative modified at Lys-11 and its activity was mostly retained. The other was a derivative modified at both Lys-11 and Lys-72 and its activity was 40% that of unmodified enzyme. Trinitrophenylation of Lys-72 appeared to bring about a conformational disorder at the lipid-water interface recognition site and thus a reduction of activity. When the enzyme was modified in the presence of Ca2+, activity decreased at a rate much faster than that in the absence of Ca2+ and Lys-69 came to be modified. These results suggested that conformational displacement of Asp-49-PLA2 of a local to global type occurs upon the binding of Ca2+. The derivative modified at Lys-69 had 28% activity and existed as a monomer. This supports a previous assumption that Lys-69 participates in dimerization of group II Asp-49-PLA2s Brunie et al. (1985) J. Biol. Chem. 260, 9742-9749 and shows that dimerization is not necessarily essential for activity manifestation.<p /><p>Language: en</p>
%G en
%I John Wiley and Sons
%@ 0952-3499
%U http://dx.doi.org/10.1002/(SICI)1099-1352(199601)9:1&lt;23::AID-JMR235&gt;3.0.CO;2-P