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PDBsum entry 4ib1
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Transferase/peptide
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PDB id
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4ib1
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References listed in PDB file
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Key reference
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Title
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Metal-Free camp-Dependent protein kinase can catalyze phosphoryl transfer.
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Authors
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O.Gerlits,
A.Das,
M.M.Keshwani,
S.Taylor,
M.J.Waltman,
P.Langan,
W.T.Heller,
A.Kovalevsky.
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Ref.
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Biochemistry, 2014,
53,
3179-3186.
[DOI no: ]
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PubMed id
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Note: In the PDB file this reference is
annotated as "TO BE PUBLISHED". The citation details given above have
been manually determined.
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Abstract
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X-ray structures of several ternary product complexes of the catalytic subunit
of cAMP-dependent protein kinase (PKAc) have been determined with no bound metal
ions and with Na(+) or K(+) coordinated at two metal-binding sites. The
metal-free PKAc and the enzyme with alkali metals were able to facilitate the
phosphoryl transfer reaction. In all studied complexes, the ATP and the
substrate peptide (SP20) were modified into the products ADP and the
phosphorylated peptide. The products of the phosphotransfer reaction were also
found when ATP-γS, a nonhydrolyzable ATP analogue, reacted with SP20 in the
PKAc active site containing no metals. Single turnover enzyme kinetics
measurements utilizing (32)P-labeled ATP confirmed the phosphotransferase
activity of the enzyme in the absence of metal ions and in the presence of
alkali metals. In addition, the structure of the apo-PKAc binary complex with
SP20 suggests that the sequence of binding events may become ordered in a
metal-free environment, with SP20 binding first to prime the enzyme for
subsequent ATP binding. Comparison of these structures reveals conformational
and hydrogen bonding changes that might be important for the mechanism of
catalysis.
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