STRUCTURAL STUDIES ASSOCIATED WITH THE CATALYSIS OF FATTY ACID SYNTHASE

这个子项目是利用由NIH/NCRR资助的中心拨款提供的资源的许多研究子项目之一。子项目和调查员(PI)可能从另一个NIH来源获得了主要资金，因此可能会出现在其他CRISE条目中。列出的机构是针对中心的，而不一定是针对调查员的机构。脂肪酸合成酶(Fas)催化脂肪酸从头合成，在胚胎发育和能量平衡中起着重要作用。Fas抑制剂有可能治疗肥胖症，从而降低相关心血管疾病和癌症的风险。动物胞浆Fas是一种272 kDa的多酶多肽，需要二聚体才能发挥活性。生化证据表明，Fas亚基呈现出一种盘绕的、头对头的结构。这一模型已被我们随后用电子显微镜(EM)对单个Fas颗粒的结构表征所证实，并与最近发表的晶体结构相一致。然而，在这两个结构中都没有鉴定出羧基末端结构域，这与它们的已知构象迁移率一致。我们建议继续我们对Fas的EM研究，以明确地确定这些可移动的羧基末端结构域的位置，并研究Fas二聚体在脂肪酸合成的每一步中所呈现的构象。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Fatty acid synthase (FAS) catalyzes the de novo synthesis of fatty acids and plays an essential role in embryogenesis and energy homeostasis. Inhibitors of FAS have the potential as treamtents for obesity, thereby reducing the risk for related cardiovascular diseases, and for cancer. The animal cytosolic FAS is a 272 kDa multienzyme polypeptide that requires dimerization for activity. Biochemical evidence suggests that FAS subunits assume a coiled, head-to-head architecture. This model has been substantiated by our subsequent structural characterization of single FAS particles by electron microscopy (EM) and is consistent with a recently published crystal structure. However in both structures the carboxyl-terminal domains were not identified, consistent with their known conformational mobility. We propose to continue our investigations of FAS by EM to unequivocally determine locations of these mobile carboxyl terminal domains and to investigate the conformations assumed by the FAS dimer at each step in fatty acid synthesis.