3rw9

Publication Abstract from PubMed

Aminopropyltransferases are essential enzymes that form polyamines in eukaryotic and most prokaryotic cells. Spermidine synthase (SpdS) is one of the most well-studied enzymes in this biosynthetic pathway. The enzyme uses decarboxylated S-adenosylmethionine and a short-chain polyamine (putrescine) to make a medium-chain polyamine (spermidine) and 5'-deoxy-5'-methylthioadenosine as a byproduct. Here, we report a new spermidine synthase inhibitor, decarboxylated S-adenosylhomocysteine (dcSAH). The inhibitor was synthesized, and dose-dependent inhibition of human, Thermatoga maritima, and Plasmodium falciparum spermidine synthases, as well as functionally homologous human spermine synthase, was determined. The human SpdS/dcSAH complex structure was determined by X-ray crystallography at 2.0 A resolution and showed consistent active site positioning and coordination with previously known structures. Isothermal calorimetry binding assays confirmed inhibitor binding to human SpdS with K(d) of 1.1 +/- 0.3 muM in the absence of putrescine and 3.2 +/- 0.1 muM in the presence of putrescine. These results indicate a potential for further inhibitor development based on the dcSAH scaffold.

Binding and inhibition of human spermidine synthase by decarboxylated S-adenosylhomocysteine.,Seckute J, McCloskey DE, Thomas HJ, Secrist JA 3rd, Pegg AE, Ealick SE Protein Sci. 2011 Aug 24. doi: 10.1002/pro.717. PMID:21898642^[1]

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