On the binding of ATP to the autophosphorylating protein, Ptk, of the bacterium Acinetobacter johnsonii

• Published in: FEBS letters 1999-02, Vol.445 (1), p.137-143
• Main Authors: Doublet, P, Vincent, C, Grangeasse, C, Cozzone, A.J, Duclos, B
• Format: Article
• Language: English
• Subjects: Acinetobacter - enzymology; Adenosine Triphosphate - metabolism; Amino Acid Sequence; ATP binding site; Autophosphorylation mechanism; Bacterial protein phosphorylation; Base Sequence; Binding Sites; Biochemistry, Molecular Biology; Glutathione Transferase - biosynthesis; Glutathione Transferase - genetics; Life Sciences; Molecular Sequence Data; Phosphates; Phosphorylation; Protein-Tyrosine Kinases - genetics; Protein-Tyrosine Kinases - metabolism; Recombinant Fusion Proteins - genetics; Recombinant Fusion Proteins - metabolism
• ISSN: 0014-5793; 1873-3468
• DOI: 10.1016/S0014-5793(99)00111-8

The autophosphorylating protein, Ptk, of the bacterium Acinetobacter johnsonii was overproduced, purified to homogeneity and assayed for ATP binding by using the nucleotide analog 5′- p-fluorosulfonylbenzoyl adenosine. The ATP binding site of this bacterial autophosphorylating protein was found to be different from that generally used by eukaryotic protein kinases. It consists of two amino acid sequences that closely resemble the Walker motifs A and B. This observation was confirmed by site-directed mutagenesis experiments which showed, in addition, that the ATP molecule bound to these motifs is effectively employed by the bacterial protein to autophosphorylate on tyrosine. It is concluded that even though the overall autophosphorylation reaction is similar in eukaryotic and prokaryotic proteins, the mechanism involved is likely different.