Study of the Dynamic Binding, Structure-Function of CIII

CIII的动态结合、结构-功能研究

• 批准号: 6917851
• 负责人: EMELITA D BREYER
• 金额: $ 13.77万
• 依托单位: GEORGIA STATE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-07-15 至 2008-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6917851
• 关键词: SDS polyacrylamide gel electrophoresis; apolipoproteins; cardiovascular disorder risk; clinical research; enzyme linked immunosorbent assay; hepatic lipase; high density lipoproteins; human tissue; lipid metabolism; lipoprotein lipase; low density lipoprotein; polymerase chain reaction; protein binding; protein protein interaction; protein structure function; scanning electron microscopy; site directed mutagenesis

DESCRIPTION (provided by applicant): Recent study shows that Apolipoprotein CIII (CIII) specifically binds and inhibits Lipoprotein Lipase (LpL) and Hepatic Lipase (HL) enzymes. The significance of the N-terminal domain in stabilizing the lipid-protein interaction and displacing Apolipoprotein E (E) was also identified (1). Our previous study that confirms the ability of CIII to displace E (2), sets up the stage for further structure-function studies evaluating the factors that enable CIII to displace E, and inhibits both HL and LpL. These functions should be investigated in correlation to CIIl's ability to bind to the lipoprotein particle (Lp) with varying size and composition. The cooperative and complex conformational modification of CIII binding to Lp and LpL/HL suggests that this study requires a factorial design experiment that can extract latent variable (factors) from collinear measurements of the protein's physico-chemical properties and structure (X-matrix), and relate these factors to the extracted latent variables from the Y-matrix consisting of the protein's functions. This study will be the first attempt to evaluate the structural factors in CIII that is responsible for the above functions in a systematic way using a factorial designed experiments. By using our model structure of CIII generated by homology with E crystal structure followed by molecular mechanics modeling, we are able to identify significant residues in CIII that may give us information regarding the difference in its function with respect to E and CII. Structural factors such as helix length, positive helix cap, loop flexibility, and hydrophobicity of side chains will be evaluated using different constructs in order to assess their contribution to the different functions of CIII. This approach is designed to give us a surface plot describing how the structural factors of CIII correlate with its functions. A more structured search and prediction of Clll analog that has a high lipid binding ability but with lipase inhibitory sites replaced by either the activating site of CII or E can be made using this approach.

描述（由申请人提供）： 最近的研究表明，载脂蛋白CIII（CIII）特异性结合并抑制脂蛋白脂肪酶（LPL）和肝脂肪酶（HL）酶。还鉴定了N末端结构域在稳定脂质蛋白相互作用和置换载脂蛋白E（E）中的重要性（1）。我们先前的研究证实了CIII置换E（2）的能力，为进一步的结构功能研究设置了阶段，以评估能够使CIII置换E的因素，并抑制HL和LPL。这些功能应与CIIL与脂蛋白颗粒（LP）结合具有不同大小和组成的能力相关。 CIII与LP和LPL/HL的结合的合作和复杂的构象修饰表明，这项研究需要一个阶乘设计实验，可以从蛋白质物理学化学特性和结构（X-Matrix）的共线测量中提取潜在变量（因子），并将这些因素与这些因素相关联，这些因素与提取的潜在变量相关联。这项研究将是评估CIII中结构因素的首次尝​​试，该因素是使用阶乘设计的实验以系统的方式负责上述功能的。通过使用与E晶体结构的同源性生成的CIII模型结构，然后进行分子力学建模，我们能够识别CIII中的重要残基，这些残基可能会为我们提供有关其功能相对于E和CII的功能差异的信息。将使用不同的构造来评估结构因子，例如螺旋长度，正螺旋盖，环柔韧性和侧链的疏水性，以评估其对CIII不同功能的贡献。这种方法旨在为我们提供一个表面图，描述了CIII的结构因子与其功能的相关性。具有较高脂质结合能力的CLLL类似物的更结构化的搜索和预测，但可以使用这种方法代替脂肪酶抑制位点，以CII或E的活化位点代替。