ISSN:
0887-3585
Schlagwort(e):
venom toxin
;
protein-membrane interaction
;
X-ray diffraction
;
spectroscopy
;
quaternary structural change
;
Chemistry
;
Biochemistry and Biotechnology
Quelle:
Wiley InterScience Backfile Collection 1832-2000
Thema:
Medizin
Notizen:
Bothropstoxin I (BthTX-I) from the venom of Bothrops jararacussuis a myotoxic phospholipase A2 (PLA2) homologue which, although catalytically inactive due to an Asp49→Lys substitution, disrupts the integrity of lipid membranes by a Ca2+-independent mechanism. The crystal structures of two dimeric forms of BthTX-I which diffract X-rays to resolutions of 3.1 and 2.1 Å have been determined. The monomers in both structures are related by an almost perfect twofold axis of rotation and the dimer interfaces are defined by contacts between the N-terminal α-helical regions and the tips of the β-wings of partner monomers. Significant differences in the relative orientation of the monomers in the two crystal forms results in “open” and “closed” dimer conformations. Spectroscopic investigations of BthTX-I in solution have correlated these conformational differences with changes in the intrinsic fluorescence emission of the single tryptophan residues located at the dimer interface. The possible relevance of this structural transition in the Ca2+-independent membrane damaging activity is discussed. Proteins 30:442-454, 1998. © 1998 Wiley-Liss, Inc.
Zusätzliches Material:
6 Ill.
Materialart:
Digitale Medien
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