Structural Basis of the Substrate Specificity and Enzyme Catalysis of a Papaver somniferum Tyrosine Decarboxylase.

Huai Guan,Qian Han,Jing Liang,Howard Robinson,Jianyong Li,Haizhen Ding,Shuaibao Song

doi:10.3389/fmolb.2017.00005

Abstract

Tyrosine decarboxylase (TyDC), a type II pyridoxal 5′-phosphate decarboxylase, catalyzes the decarboxylation of tyrosine. Due to a generally high sequence identity to other aromatic amino acid decarboxylases (AAADs), primary sequence information is not enough to understand substrate specificities with structural information. In this study, we selected a typical TyDC from Papaver somniferum as a model to study the structural basis of AAAD substrate specificities. Analysis of the native P. somniferum TyDC crystal structure and subsequent molecular docking and dynamics simulation provide some structural bases that explain substrate specificity for tyrosine. The result confirmed the previous proposed mechanism for the enzyme selectivity of indolic and phenolic substrates. Additionally, this study yields the first crystal structure for a plant type II pyridoxal-5'-phosphate decarboxylase.

Highlights

Tyrosine decarboxylase (TyDC) (EC 4.1.1.25) is a member of aromatic amino acid decarboxylases (AAADs), which are a group of phylogenetically diverse enzymes grouped together based on theirStructural Biology, pyridoxal 5′-phosphate (PLP) dependence and sequence homology
We reported the first crystal structure of a plant type II PLP decarboxylase
Analysis of the active site conformation of P. somniferum TyDC 9 crystal structure provided some structural basis for its ability to adapt a phenolic substrate

Summary

Introduction

Tyrosine decarboxylase (TyDC) (EC 4.1.1.25) is a member of aromatic amino acid decarboxylases (AAADs), which are a group of phylogenetically diverse enzymes grouped together based on their. Structural Biology, pyridoxal 5′-phosphate (PLP) dependence and sequence homology. AAADs catalyze key reactions a section of the journal in a diverse set of pathways impacting the synthesis of neurotransmitters in animals, insects; Frontiers in Molecular Biosciences (Nassel, 1996; Osborne, 1996; Schwartz, 2000; Neckameyer and Leal, 2002) and alkaloids, aromatic. Published: 09 February 2017 AAAD enzymes are involved in egg maturation, immune responses, and muscle development. Liang J, Ding H, Li J and Han Q (2017) Structural Basis of the Substrate Specificity and Enzyme Catalysis of a Papaver somniferum.

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