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Title
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Three-dimensional structure of echistatin, the smallest active RGD protein.
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Authors
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V.Saudek,
R.A.Atkinson,
J.T.Pelton.
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Ref.
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Biochemistry, 1991,
30,
7369-7372.
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PubMed id
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Abstract
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Echistatin is a 49 amino acid protein isolated from the venom of a viper (Echis
carinatus) and is one of the smallest natural adhesive ligands that interacts
with integrin-type receptors through an Arg-Gly-Asp (RGD) sequence. The
structure of echistatin in aqueous solution has been determined by nuclear
magnetic resonance spectroscopy. Nuclear Overhauser spectra yielded 490
interatomic distance constraints, which were used in distance geometry
calculations. The chain is shown to fold in a series of irregular loops to form
a rigid core stabilized by four cystine cross-links. From this core an irregular
hairpin and the C-terminus protrude. The core and the hairpin are further
stabilized by a network of hydrogen bonds. The RGD sequence is located in a
mobile loop at the tip of the hairpin. The mobility and its significance for
activity are discussed.
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