ISOLATION AND BIOINFORMATICS ANALYSIS OF GLUTAMYL-TRNA REDUCTASE IN CHINESE JUJUBE.

Tetrapyrroles, such as chlorophyll and heme, are integral to the metabolism of all living organisms. Glutamyl-tRNA reductase (GluTR) is the first unique enzyme in the tetrapyrrole biosynthetic pathway in plants. We firstly cloned the GluTR complete sequences (1733 bp) from Chinese jujube (Ziziphus jujuba Mill., belonging to the family Rhamnaceae), named as ZjGluTR (GenBank accession no. KF530842). ZjGluTR shares high similarity (90%) to those of Malus domestica and Prunus mume through BLASTX analysis. It contains a 1659-bp ORF and encodes a predicted polypeptide of 552 amino acids, with an estimated molecular mass of 60.0 kDa and a theoretical pI of 8.55. The speculated formula of ZjGluTR is C₂₆₁₅H₄₃₁₈N₇₅₆ O₈₀₄S₂₅. ZjGluTR has a chloroplast transit peptide which contains 61 amino acids in the N terminal. The subcellular localization result showed that ZjGluTR protein exists in chloroplasts. ZjGluTR has three typical functional domains, i.e. GluTR N-terminal domain (101-259 aa), NAD(P)-binding Rossmann-fold domain (266-422 aa) and GluTR dimerization domain (425-534 aa). The molecular phylogenetic tree of GluTR indicated that the family Rhamnaceae has a close genetic relationship with the family Rosaceae. Our studies on the GluTR using molecular biology and bioinformatics approaches would play an important role in chlorophyll metabolic research of Chinese jujube. [ABSTRACT FROM AUTHOR]