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Surface topology of Minibody by selective chemical modifications and mass spectrometry
Author(s) -
Zappacosta Francesca,
Ingallinella Paolo,
Scaloni Andrea,
Pessi Antonello,
Bianchi Elisabetta,
Sollazzo Maurizio,
Tramontano Anna,
Marino Gennaro,
Pucci Piero
Publication year - 1997
Publication title -
protein science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.353
H-Index - 175
eISSN - 1469-896X
pISSN - 0961-8368
DOI - 10.1002/pro.5560060911
Subject(s) - chemistry , mass spectrometry , proteolysis , reactivity (psychology) , protein tertiary structure , intramolecular force , topology (electrical circuits) , molecule , protein structure , stereochemistry , organic chemistry , biochemistry , enzyme , chromatography , medicine , alternative medicine , mathematics , pathology , combinatorics
The surface topology of the Minibody, a small de novo‐designed β‐protein, has been probed by a strategy that combines selective chemical modification with a variety of reagents and mass spectrometric analysis of the modified fragments. Under appropriate conditions, the susceptibility of individual residues primarily depends on their surface accessibility so that their relative reactivities can be correlated with their position in the tertiary structure of the protein. Moreover, this approach provides information on interacting residues, since intramolecular interactions might greatly affect the reactivity of individual side chains by altering their pKa values. The results of this study indicate that, while overall the Minibody model is correct, the β‐sheet formed by the N‐ and C‐terminal segments is most likely distorted. This is also in agreement with previous results that were obtained using a similar approach where mass spectrometry was used to identify Minibody fragments from limited proteolysis (Zappacosta F, Pessi A, Bianchi E, Venturini s, Sollazzo M, Tramontano A, Marino G, Pucci P. 1996. Probing the tertiary structure of proteins by limited proteolysis and mass spectrometry: The case of Minibody. Protein Sci 5902‐813). The chemical modification approach, in combination with limited proteolysis procedures, can provide useful, albeit partial, structural information to complement simulation techniques. This is especially valuable when, as in the Minibody case, an NMR and/or X‐ray structure cannot be obtained due to insufficient solubility of the molecule.