Pace C N
Department of Medical Biochemistry and Genetics and Biochemistry and Biophysics and Center for Advanced Biomolecular Research, Texas A&M University, College Station, Texas 77843-1114, USA.
Biochemistry. 2001 Jan 16;40(2):310-3. doi: 10.1021/bi001574j.
On the basis of studies of Asn to Ala mutants, the gain in stability from burying amide groups that are hydrogen bonded to peptide groups is 80 cal/(mol A(3)). On the basis of similar studies of Leu to Ala and Ile to Val mutants, the gain in stability from burying -CH(2)- groups is 50 cal/(mol A(3)). Thus, the burial of an amide group contributes more to protein stability than the burial of an equivalent volume of -CH(2)- groups. Applying these results to folded proteins leads to the surprising conclusion that peptide group burial makes a larger contribution to protein stability than nonpolar side chain burial. Several studies have shown that the desolvation penalty for burying peptide groups is considerably smaller than generally thought. This suggests that the hydrogen bonding and van der Waals interactions of peptide groups in the tightly packed interior of folded protein are more favorable than similar interactions with water in the unfolded protein.
基于对天冬酰胺（Asn）突变为丙氨酸（Ala）的突变体的研究，将与肽基团形成氢键的酰胺基团埋入所带来的稳定性增加为80卡/（摩尔·埃³）。基于对亮氨酸（Leu）突变为丙氨酸以及异亮氨酸（Ile）突变为缬氨酸（Val）的突变体的类似研究，将-CH₂-基团埋入所带来的稳定性增加为50卡/（摩尔·埃³）。因此，酰胺基团的埋入对蛋白质稳定性的贡献比等体积-CH₂-基团的埋入更大。将这些结果应用于折叠蛋白质会得出一个惊人的结论，即肽基团的埋入对蛋白质稳定性的贡献比非极性侧链的埋入更大。多项研究表明，将肽基团埋入时的去溶剂化惩罚比通常认为的要小得多。这表明在折叠蛋白质紧密堆积的内部，肽基团的氢键和范德华相互作用比与未折叠蛋白质中的水的类似相互作用更有利。
