Structural insight into the substrate inhibition mechanism of NADP+-dependent succinic semialdehyde dehydrogenase from Streptococcus pyogenesStructural insight into the substrate inhibition mechanism of NADP+-dependent succinic semialdehyde dehydrogenase from Streptococcus pyogenes

Structural highlights

4ywu is a 2 chain structure with sequence from Streptococcus pyogenes MGAS1882. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance.
Method:X-ray diffraction, Resolution 2.4Å
Ligands:,
Resources:FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT

Function

A0A0J9X1M8_STRPY

Publication Abstract from PubMed

Succinic semialdehyde dehydrogenases (SSADHs) are ubiquitous enzymes that catalyze the oxidation of succinic semialdehyde (SSA) to succinic acid in the presence of NAD(P)+, and play an important role in the cellular mechanisms including the detoxification of accumulated SSA or the survival in conditions of limited nutrients. Here, we report the inhibitory properties and two crystal structures of SSADH from Streptococcus pyogenes (SpSSADH) in a binary (ES) complex with SSA as the substrate and a ternary (ESS) complex with the substrate SSA and the inhibitory SSA, at 2.4 A resolution for both structures. Analysis of the kinetic inhibitory parameters revealed significant substrate inhibition in the presence of NADP+ at concentrations of SSA higher than 0.02 mM, which exhibited complete uncompetitive substrate inhibition with the inhibition constant (Ki) value of 0.10 +/- 0.02 mM. In ES-complex of SpSSADH, the SSA showed a tightly bound bent form nearby the catalytic residues, which may be caused by reduction of the cavity volume for substrate binding, compared with other SSADHs. Moreover, structural comparison of ESS-complex with a binary complex with NADP+ of SpSSADH indicated that the substrate inhibition was induced by the binding of inhibitory SSA in the cofactor-binding site, instead of NADP+. Our results provide first structure-based molecular insights into the substrate inhibition mechanism of SpSSADH as the Gram-positive bacterial SSADH.

Structural insight into the substrate inhibition mechanism of NADP-dependent succinic semialdehyde dehydrogenase from Streptococcus pyogenes.,Jang EH, Park SA, Chi YM, Lee KS Biochem Biophys Res Commun. 2015 Apr 16. pii: S0006-291X(15)00725-1. doi:, 10.1016/j.bbrc.2015.04.047. PMID:25888791[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

See Also

References

  1. Jang EH, Park SA, Chi YM, Lee KS. Structural insight into the substrate inhibition mechanism of NADP-dependent succinic semialdehyde dehydrogenase from Streptococcus pyogenes. Biochem Biophys Res Commun. 2015 Apr 16. pii: S0006-291X(15)00725-1. doi:, 10.1016/j.bbrc.2015.04.047. PMID:25888791 doi:http://dx.doi.org/10.1016/j.bbrc.2015.04.047

4ywu, resolution 2.40Å

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