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Discriminatory recognition of membrane phospholipids by lysine‐49‐phospholipases A 2 from Trimeresurus flavoviridis venom
Author(s) -
Shimohigashi Yasuyuki,
Tani Ayoko,
Yamaguchi Yoko,
Ogawi Tomahisa,
Ohno Motonori
Publication year - 1996
Publication title -
journal of molecular recognition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.401
H-Index - 79
eISSN - 1099-1352
pISSN - 0952-3499
DOI - 10.1002/(sici)1099-1352(199634/12)9:5/6<639::aid-jmr313>3.0.co;2-x
Subject(s) - venom , lysine , phospholipase , phospholipase a2 , chemistry , biology , biochemistry , enzyme , amino acid
Basic proteins I and II (BP‐I and BP‐II) isolated from Trimeresurus flavoviridis venom, which are classified into a group of lysine‐49‐phospholipases A 2 (Lys‐49‐PLA 2 ), exhibited only limited lipolytic activity for the mixed micelles of various phospholipids. Based on the finding that BP‐II elicits a strong contraction of guinea pig ileum due to the release of arachidonic acid, BP‐II together with BP‐I has been tested for their interaction with artificial phospholipid bilayer membranes. The dye leakage experiments indicated that BP‐II interacts strongly with liposomes of β ‐arachidonoyl‐ γ ‐stearoyl‐ L α ‐phosphatidylcholine. The perturbation of liposomes was observed only in the Ca 2+ ‐containing buffer, and as demonstrated by HPLC analyses, accompanied by the release of arachidonic acid. The concentration of Ca 2+ which gave a half maximal activity of BP‐II was 3.0 × 10 −4 M , suggesting that the affinity of BP‐II for Ca 2+ is more than 10 times stronger than that of BP‐II without liposomes. These observations clearly show that Lys‐49‐PLA 2 of BP‐II is the enzyme responsible for the hydrolysis of membrane phospholipids and that Ca 2+ is essential for such enzymatic activity. The interaction of BP‐I with liposomes was much weaker than BP‐II. BP‐I and BP‐II share a common sequence except for Asp‐67 (BP‐I) and Asn‐67 (BP‐II) in the aligned sequences. This implies that the amino acid at position 67 of Lys‐49‐PLA 2 s is the residue required for discriminatory recognition of phospholipid membranes.