Three phosphorylation sites in elongation factor 2.
Elongation factor 2 (EF-2) of rabbit reticulocytes was phosphorylated in vitro by incubation with partially purified EF-2 kinase and [gamma-32P]ATP. After exhaustive tryptic hydrolysis 4 phosphopeptides were revealed by two-dimensional peptide mapping. The phosphopeptides were isolated by high performance liquid chromatography and sequenced. A comparison of the primary structure of the phosphopeptides with that of EF-2 showed that all 4 phosphopeptides originated from one region of EF-2 located near the N-terminus that contains 3 threonine residues: Thr-53, Thr-56, Thr-58. A direct estimation of localization of radioactive phosphate in the phosphopeptides demonstrated that all the enumerated threonine residues in EF-2 can be phosphorylated in vitro.
Ovchinnikov
L P
LP
Institute of Protein Research, Academy of Sciences of the USSR, Pushchino, Moscow Region.
Motuz
L P
LP
Natapov
P G
PG
Averbuch
L J
LJ
Wettenhall
R E
RE
Szyszka
R
R
Kramer
G
G
Hardesty
B
B
D000255:Adenosine Triphosphate / Q000378:metabolism; D000595:Amino Acid Sequence; D000818:Animals; D017871:Calcium-Calmodulin-Dependent Protein Kinases; D054736:Elongation Factor 2 Kinase; D008969:Molecular Sequence Data; D020652:Peptide Elongation Factor 2; D010445:Peptide Elongation Factors / Q000378:metabolism*; D010446:Peptide Fragments / Q000737:chemistry; D010766:Phosphorylation; D010769:Phosphothreonine / Q000378:metabolism*; D011494:Protein Kinases / Q000378:metabolism*; D011817:Rabbits; D012156:Reticulocytes
D020652:Peptide Elongation Factor 2; D010445:Peptide Elongation Factors; D010446:Peptide Fragments; D010769:Phosphothreonine; D000255:Adenosine Triphosphate; D011494:Protein Kinases; D017871:Calcium-Calmodulin-Dependent Protein Kinases; D054736:Elongation Factor 2 Kinase