Crystal structures of human and Staphylococcus aureus pyruvate carboxylase and molecular insights the carboxyltransfer reaction
Crystal structures of human and Staphylococcus aureus pyruvate carboxylase and molecular insights the carboxyltransfer reaction
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DOI：
10.1038/nsmb.1393
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发表时间：
2008-03-01
影响因子：
16.8
通讯作者：
Tong, Liang
中科院分区：
文献类型：
--
作者：
Xiang, Song;Tong, Liang
丙酮酸羧化酶（Pyruvate carboxylase， PC）催化生物素依赖性草酰乙酸的生成，在糖异生、脂肪生成、胰岛素分泌等细胞过程中发挥重要作用。PC包含生物素羧化酶（BC）、羧化转移酶（CT）和生物素-羧基载体蛋白（BCCP）结构域。本文报道了金黄色葡萄球菌全长PC的2.8埃分辨率晶体结构和人类PC的c端区（仅缺失BC结构域）。这两种酶都存在保守的四聚体关联，我们的结构和诱变研究揭示了一个以前未被表征的结构域，即PC四聚化（PT）结构域，这对寡聚化很重要。BCCP结构域位于CT结构域的活性位点，为生物素如何参与羧基转移反应提供了第一个分子见解。这些酶与来自根瘤菌的PC在单体结构域位置和四聚体的组织结构上存在显著差异。
Pyruvate carboxylase (PC) catalyzes the biotin-dependent production of oxaloacetate and has important roles in gluconeogenesis, lipogenesis, insulin secretion and other cellular processes. PC contains the biotin carboxylase (BC), carboxyltransferase (CT) and biotin-carboxyl carrier protein (BCCP) domains. We report here the crystal structures at 2.8-angstrom resolution of full-length PC from Staphylococcus aureus and the C-terminal region (missing only the BC domain) of human PC. A conserved tetrameric association is observed for both enzymes, and our structural and mutagenesis studies reveal a previously uncharacterized domain, the PC tetramerization (PT) domain, which is important for oligomerization. A BCCP domain is located in the active site of the CT domain, providing the first molecular insights into how biotin participates in the carboxyltransfer reaction. There are dramatic differences in domain positions in the monomer and the organization of the tetramer between these enzymes and the PC from Rhizobium etli.