3ccd
1.0 A Structure of Post-Succinimide His15Asp HPr
Structural highlights
FunctionPTHP_ECOLI General (non sugar-specific) component of the phosphoenolpyruvate-dependent sugar phosphotransferase system (sugar PTS). This major carbohydrate active-transport system catalyzes the phosphorylation of incoming sugar substrates concomitantly with their translocation across the cell membrane. The phosphoryl group from phosphoenolpyruvate (PEP) is transferred to the phosphoryl carrier protein HPr by enzyme I. Phospho-HPr then transfers it to the permease (enzymes II/III). 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 PubMedAspartates and asparagines can spontaneously cyclize with neighboring main-chain amides to form succinimides. These succinimides hydrolyze to a mixture of isoaspartate and aspartate products. Phosphorylation of aspartates is a common mechanism of protein regulation and increases the propensity for succinimide formation. Although typically regarded as a form of protein damage, we hypothesize succinimides could represent an effective mechanism of phosphoaspartate autophosphatase activity, provided hydrolysis is limited to aspartate products. We previously reported the serendipitous creation of a protein, His15Asp histidine-containing protein (HPr), which undergoes phosphorylation-catalyzed formation of a succinimide whose hydrolysis is seemingly exclusive for aspartate formation. Here, through the high-resolution structure of postsuccinimide His15Asp HPr, we confirm the absence of isoaspartate residues and propose mechanisms for phosphorylation-catalyzed succinimide formation and its directed hydrolysis to aspartate. His15Asp HPr represents the first characterized protein example of an isoaspartate-free succinimide and lends credence to the hypothesis that intramolecular cyclization could represent a physiological mechanism of autophosphatase activity. Furthermore, this indicates that current strategies for succinimide evaluation, based on isoaspartate detection, underestimate the frequencies of these reactions. This is considerably significant for evaluation of protein stability and integrity. Structural investigation of a phosphorylation-catalyzed, isoaspartate-free, protein succinimide: crystallographic structure of post-succinimide His15Asp histidine-containing protein.,Napper S, Prasad L, Delbaere LT Biochemistry. 2008 Sep 9;47(36):9486-96. Epub 2008 Aug 15. PMID:18702519[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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