Identification of the amino acid residues responsible for cold tolerance in Flaveria brownii pyruvate,orthophosphate dikinase.
Pyruvate,orthophosphate dikinase (PPDK), an enzyme important in C4 photosynthesis, is typically a cold-sensitive enzyme. However, a cold-tolerant form of the enzyme has been isolated from the leaves of Flaveria brownii. Using an E. coli expression system and the PPDK cDNAs from F. brownii (cold-tolerant), F. bidentis (cold-sensitive) and maize (intermediately cold-tolerant), site-directed mutagenesis studies indicated that as few as three amino acids residues (of 880 residues) strongly influence the cold sensitivity of Flaveria PPDK. Gel filtration analysis of the PPDK expressed in E. coli showed that subunit association and cold tolerance are closely linked.
Ohta
S
S
Plant Breeding and Genetics Research Laboratory, Japan Tobacco Inc., Iwata, Shizuoka, Japan.
Usami
S
S
Ueki
J
J
Kumashiro
T
T
Komari
T
T
Burnell
J N
JN
D000595:Amino Acid Sequence; D003080:Cold Temperature; D018076:DNA, Complementary; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D010940:Plant Proteins / Q000737:chemistry / Q000235:genetics / Q000502:physiology; D010944:Plants / Q000201:enzymology*; D011772:Pyruvate, Orthophosphate Dikinase / Q000737:chemistry / Q000235:genetics / Q000502:physiology*; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D003313:Zea mays / Q000201:enzymology
D018076:DNA, Complementary; D010940:Plant Proteins; D011993:Recombinant Fusion Proteins; D011772:Pyruvate, Orthophosphate Dikinase