1s5p
From Proteopedia
Structure and substrate binding properties of cobB, a Sir2 homolog protein deacetylase from Eschericia coli.
Structural highlights
Function[NPD_ECOLI] NAD-dependent lysine deacetylase and desuccinylase that specifically removes acetyl and succinyl groups on target proteins. Modulates the activities of several proteins which are inactive in their acylated form. Activates the enzyme acetyl-CoA synthetase by deacetylating 'Lys-609' in the inactive, acetylated form of the enzyme. May also modulate the activity of other propionyl-adenosine monophosphate (AMP)-forming enzymes.[1] [2] [3] Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedSirtuins are NAD+-dependent protein deacetylase enzymes that are broadly conserved from bacteria to human, and have been implicated to play important roles in gene regulation, metabolism and longevity. cobB is a bacterial sirtuin that deacetylates acetyl-CoA synthetase (Acs) at an active site lysine to stimulate its enzymatic activity. Here, we report the structure of cobB bound to an acetyl-lysine containing non-cognate histone H4 substrate. A comparison with the previously reported archaeal and eukaryotic sirtuin structures reveals the greatest variability in a small zinc-binding domain implicated to play a particularly important role in substrate-specific binding by the sirtuin proteins. Comparison of the cobB/histone H4 complex with other sirtuin proteins in complex with acetyl-lysine containing substrates, further suggests that contacts to the acetyl-lysine side-chain and beta-sheet interactions with residues directly C-terminal to the acetyl-lysine represent conserved features of sirtuin-substrate recognition. Isothermal titration calorimetry studies were used to compare the affinity of cobB for a variety of cognate and non-cognate acetyl-lysine-bearing peptides revealing an exothermic reaction with relatively little discrimination between substrates. In contrast, similar studies employing intact acetylated Acs protein as a substrate reveal a binding reaction that is endothermic, suggesting that cobB recognition of substrate involves a burial of hydrophobic surface and/or structural rearrangement involving substrate regions distal to the acetyl-lysine-binding site. Together, these studies suggest that substrate-specific binding by sirtuin proteins involves contributions from the zinc-binding domain of the enzyme and substrate regions distal to the acetyl-lysine-binding site. Structure and substrate binding properties of cobB, a Sir2 homolog protein deacetylase from Escherichia coli.,Zhao K, Chai X, Marmorstein R J Mol Biol. 2004 Mar 26;337(3):731-41. PMID:15019790[4] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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