Crystal structure of SPSB2 in complex with a rational designed RGD-containing cyclic peptide inhibitor of SPSB2-iNOS interaction.You, T., Wang, Y., Li, K., Zhang, D., Wei, H., Luo, Y., Li, H., Lu, Y., Su, X., Kuang, Z.
(2017) Biochem. Biophys. Res. Commun. 489: 346-352
- PubMed: 28549582
- DOI: 10.1016/j.bbrc.2017.05.122
- PubMed Abstract:
SPRY domain-containing SOCS box protein 2 (SPSB2) is a negative regulator of inducible nitric oxide synthase (iNOS) that modulates the lifetime of iNOS and thus the levels of nitric oxide (NO) production. Inhibitors that can disrupt the endogenous SP ...
SPRY domain-containing SOCS box protein 2 (SPSB2) is a negative regulator of inducible nitric oxide synthase (iNOS) that modulates the lifetime of iNOS and thus the levels of nitric oxide (NO) production. Inhibitors that can disrupt the endogenous SPSB2-iNOS interaction and augment NO production have potential as novel antimicrobial and anticancer drugs. In this study, we have designed a cyclic peptide (cR8), containing an RGD motif and the SPSB2 binding motif (DINNNV). ITC and chemical shift perturbation showed that cR8 binds to the iNOS binding site on SPSB2 with a Kd of 671 nM, and saturation transfer difference NMR showed that cR8 binds to αvβ3 integrin-expressing cells. Moreover, we determined the crystal structure of SPSB2 in complex with cR8, at a resolution of 1.34 Å. cR8 forms extensive hydrogen bonding with SPSB2 residues, but loss of an intramolecular hydrogen bond that is present in SPSB2-bound iNOS peptide may destabilize the bound conformation of cR8 and lead to a gentle reduction in SPSB2 binding affinity. These results serve as a useful basis for designing site-directed SPSB2 inhibitors in the future.
Department of Cell Biology and Institute of Biomedicine, Jinan University, Guangzhou 510632, China; Guangdong Provincial Key Laboratory of Bioengineering Medicine, National Engineering Research Center of Genetic Medicine, Guangzhou 510632, China.