FRAGMENT OF LAMBDA REPRESSOR (L6 85) & DOUBLE MUTANT G46A & G48A L6 85

Lambda 阻遏物片段 (L6 85)

• 批准号: 6122019
• 负责人: TERRENCE GILBERT OAS
• 金额: --
• 依托单位: JOHNS HOPKINS UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 1997
• 资助国家: 美国
• 起止时间: 1997-08-05 至 1998-08-04
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6122019
• 关键词: bioengineering /biomedical engineering; biological products; biomaterials; biomedical resource; education; genetics; human tissue; model design /development; technology /technique development

Lambda repressor (l6-85) is a soluble fragment of lambda repressor containing residues 6 to 85 which maintains a native-like fold consisting largely of alpha helices. Differential scanning calorimetry (DSC) of the WT (l6-85) and the double mutant G46A/G48A reveal that the effect of the mutations is to stabilize the protein by ~ 1.5 kcal/mol at 25 C (I.e., 2.9 kcal/mol for the WT and 4.4 kcal/mol for G46/48A). The increase in stability upon mutation suggests that the primary effect of the mutation on stability is the decrease in conformational entropy ( Sconf) of the unfolded state when Gly is replaced by Ala. However, as the calculated effect of changing Gly to Ala at two positions in a helix is ~ 2.4 kcal/mol, the ~0.9 kcal/mol difference between the experimental and calculated values suggests that additional effects arise from the mutations which decrease the stability of the native state of the double mutant.

λ阻遏物（l 6 -85）是λ阻遏物的可溶性片段 含有保留天然样折叠的残基6至85 主要由α螺旋组成。 差示扫描量 WT（16 -85）和双突变体G46 A/G48 A的量热法（DSC） 揭示了突变的作用是通过以下方式稳定蛋白质： 在25 ℃下约为1.5 kcal/mol（即，2.9 WT为4.4 kcal/mol， G46/48A）。 突变后稳定性的增加表明， 突变对稳定性的主要影响是 构象熵（Sconf）的展开状态时，Gly是 被阿拉取代。然而，由于将Gly改变为 螺旋中两个位置的Ala为~ 2.4 kcal/mol， 实验值和计算值之间的差异表明 会产生额外的影响 从降低天然状态稳定性的突变中 双重突变体的