Structural determinants and modulation of substrate specificity in phenylalanine-tyrosine ammonia-lyases
Structural determinants and modulation of substrate specificity in phenylalanine-tyrosine ammonia-lyases
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DOI：
10.1016/j.chembiol.2006.11.011
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发表时间：
2006-12-01
影响因子：
--
通讯作者：
Noel, Joseph P.
中科院分区：
文献类型：
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作者：
Louie, Gordon V.;Bowman, Marianne E.;Noel, Joseph P.
芳香族氨基酸氨裂解酶催化L-His、L-Phe和L-Tyr的脱氨基，产生氨和带有α，β-不饱和丙烯酸的芳基酸。我们报告晶体学分析的unliganded Rhodobacter sphaeroides酪氨酸氨-tyase（RsTAL）和RsTAL绑定对香豆酸和咖啡酸。RsTAL的His 89与香豆酸盐和咖啡酸盐的p-羟基部分形成氢键。His 89在TAL中是保守的，但在苯丙氨酸解氨酶（帕尔斯）和组氨酸解氨酶（HAL）中被替换。His 89被帕尔斯的特征性残基Phe取代，产生具有从L-Tyr到L-Phe的动力学偏好切换的突变体。与PAL产物肉桂酸或PAL特异性抑制剂2-氨基茚满-2-膦酸（AIP）复合的H89 F突变体的结构支持位置89作为负责β-氨基酸生物合成的芳香族氨基酸氨裂解酶和氨基变位酶家族中的特异性决定子的作用。
Aromatic amino acid ammonia-lyases catalyze the deamination of L-His, L-Phe, and L-Tyr, yielding ammonia plus aryl acids bearing an alpha, beta-unsaturated propenoic acid. We report crystallographic analyses of unliganded Rhodobacter sphaeroides tyrosine ammonia-tyase (RsTAL) and RsTAL bound to p-coumarate and caffeate. His 89 of RsTAL forms a hydrogen bond with the p-hydroxyl moieties of coumarate and caffeate. His 89 is conserved in TALs but replaced in phenylalanine ammonia-tyases (PALs) and histidine ammonia-tyases (HALs). Substitution of His 89 by Phe, a characteristic residue of PALs, yields a mutant with a switch in kinetic preference from L-Tyr to L-Phe. Structures of the H89F mutant in complex with the PAL product, cinnamate, or the PAL-specific inhibitor, 2-aminoindan-2-phosphonate (AIP), support the role of position 89 as a specificity determinant in the family of aromatic amino acid ammonia-lyases and amino-mutases responsible for beta-amino acid biosynthesis.