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Towards the Understanding of the Folding of Methylene Units in the Glutamine Residue
Author(s) -
Alemán Carlos,
Vega M. Cristina,
Navarro Eloísa,
Puiggalí Jordi
Publication year - 1996
Publication title -
journal of peptide science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.475
H-Index - 66
eISSN - 1099-1387
pISSN - 1075-2617
DOI - 10.1002/psc.75
Subject(s) - residue (chemistry) , glutamine , methylene , chemistry , stereochemistry , biochemistry , organic chemistry , amino acid
The conformational preferences of the methylenic sequence in the side chain of the glutamine residue were investigated by ab initio and semi‐empirical quantum mechanical calculations and examination of both the Brookhaven Protein Databank and Cambridge Structural Data Base. The results were analysed on the basis of our previous findings about the folding of methylene groups in aliphatic segments. Both energy calculations and the crystallographic structure of small peptides indicate that methylene units of the glutamine residue tend to fold in a gauche conformation. In contrast, such groups usually adopt an all‐ trans conformation in proteins due basically to the entropic and solvent contributions. These results have been demonstrated by computing the entropic correction to the free energy and evaluating the solvent effects through SCRF calculations