School of Life Sciences, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, Anhui 230026, People's Republic of China.
Acta Crystallogr F Struct Biol Commun. 2021 Mar 1;77(Pt 3):61-69. doi: 10.1107/S2053230X21001989. Epub 2021 Mar 3.
Anthranilate phosphoribosyltransferase (AnPRT) catalyzes the transfer of the phosphoribosyl group of 5'-phosphoribosyl-1'-pyrophosphate (PRPP) to anthranilate to form phosphoribosyl-anthranilate. Crystal structures of AnPRTs from bacteria and archaea have previously been determined; however, the structure of Saccharomyces cerevisiae AnPRT (ScAnPRT) still remains unsolved. Here, crystal structures of ScAnPRT in the apo form as well as in complex with its substrate PRPP and the substrate analogue 4-fluoroanthranilate (4FA) are presented. These structures demonstrate that ScAnPRT exhibits the conserved structural fold of type III phosphoribosyltransferase enzymes and shares the similar mode of substrate binding found across the AnPRT protein family. In addition, crystal structures of ScAnPRT mutants (ScAnPRT and ScAnPRT) were also determined. These structures suggested that the conserved residue Ser121 is critical for binding PRPP, while Gly141 is dispensable for binding 4FA. In summary, these structures improved the preliminary understanding of the substrate-binding mode of ScAnPRT and laid foundations for future research.
芳香族氨基酸磷酸核糖基转移酶（AnPRT）催化 5'-磷酸核糖基-1'-焦磷酸（PRPP）的磷酸核糖基转移到邻氨基苯甲酸上，形成磷酸核糖基邻氨基苯甲酸。先前已经确定了来自细菌和古菌的 AnPRT 的晶体结构；然而，酿酒酵母 AnPRT（ScAnPRT）的结构仍然未解决。本文呈现了 ScAnPRT 的apo 形式以及与底物 PRPP 和底物类似物 4-氟邻氨基苯甲酸（4FA）复合物的晶体结构。这些结构表明，ScAnPRT 表现出 III 型磷酸核糖基转移酶酶的保守结构折叠，并共享在 AnPRT 蛋白家族中发现的类似的底物结合模式。此外，还确定了 ScAnPRT 突变体（ScAnPRT 和 ScAnPRT）的晶体结构。这些结构表明保守残基 Ser121 对于结合 PRPP 至关重要，而 Gly141 对于结合 4FA 则不是必需的。总之，这些结构提高了对 ScAnPRT 底物结合模式的初步理解，并为未来的研究奠定了基础。
