The evolution of glutamate synthase


Dincturk H., Knaff D.

MOLECULAR BIOLOGY REPORTS, cilt.27, ss.141-148, 2000 (SCI İndekslerine Giren Dergi) identifier identifier identifier

  • Cilt numarası: 27 Konu: 3
  • Basım Tarihi: 2000
  • Doi Numarası: 10.1023/a:1007107909619
  • Dergi Adı: MOLECULAR BIOLOGY REPORTS
  • Sayfa Sayıları: ss.141-148

Özet

DNA coding for the ferredoxin-dependent glutamate synthase (EC1.4.7.1) of spinach chloroplasts has been cloned and sequenced. It consists of 5015 bp and starts with the codon for the N-terminal cysteine of the mature protein. Ferredoxin-dependent glutamate synthase is one of the key enzymes in the early stages of ammonia assimilation in plants, algae and cyanobacteria. In addition to the ferredoxin-dependent enzyme, there are two other forms of glutamate synthase, one of which uses NADH as the electron donor and a second that uses NADPH. Although all three forms catalyze the reductive transamidation of the amido nitrogen from glutamine to 2-oxoglutarate to form two molecules of glutamate, ferredoxin-dependent glutamate synthases differ from the NADH and NADPH-dependent forms in subunit composition and amino acid sequence. The recent availability of sequence data for glutamate synthases from spinach and from two archael species has produced a clearer and more detailed picture of the evolution of this key enzyme in nitrogen metabolism and the origins of the two subunit/domain structure of the enzyme.