2nqg
From Proteopedia
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| , resolution 2.04Å | |||||||
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| Ligands: | , | ||||||
| Gene: | Capn1, Cls1 (Rattus norvegicus) | ||||||
| Activity: | Calpain-1, with EC number 3.4.22.52 | ||||||
| Related: | 2NQI, 1TLO, 2G8J, 2G8E, 1TL9, 1ZCM, 1KXR
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| Resources: | FirstGlance, OCA, PDBsum, RCSB | ||||||
| Coordinates: | save as pdb, mmCIF, xml | ||||||
Calpain 1 proteolytic core inactivated by WR18(S,S), an epoxysuccinyl-type inhibitor.
Overview
Calpains are calcium-dependent proteases that are required for numerous intracellular processes but also play an important role in the development of pathologies such as ischemic injury and neurodegeneration. Many current small molecule calpain inhibitors also inhibit other cysteine proteases, including cathepsins, and need improved selectivity. The specificity of inhibition of several calpains and papain was profiled using synthetic positional scanning libraries of epoxide-based compounds that target the active-site cysteine. These peptidomimetic libraries probe the P4, P3, and P2 positions, display (S,S)- or (R,R)-epoxide stereochemistries, and incorporate both natural and non-natural amino acids. To facilitate library screening, an SDS-PAGE assay that measures the extent of hydrolysis of an inactive recombinant m-calpain was developed. Individual epoxide inhibitors were synthesized guided by calpain-specific preferences observed from the profiles and tested for inhibition against calpain. The most potent compounds were assayed for specificity against cathepsins B, L, and K. Several compounds demonstrated high inhibition specificity for calpains over cathepsins. The best of these inhibitors, WRH(R,R), irreversibly inactivates m- and mu-calpain rapidly (k(2)/K(i) = 131,000 and 16,500 m(-1) s(-1), respectively) but behaves exclusively as a reversible and less potent inhibitor toward the cathepsins. X-ray crystallography of the proteolytic core of rat mu-calpain inactivated by the epoxide compounds WR gamma-cyano-alpha-aminobutyric acid (S,S) and WR allylglycine (R,R) reveals that the stereochemistry of the epoxide influences positioning and orientation of the P2 residue, facilitating alternate interactions within the S2 pocket. Moreover, the WR gamma-cyano-alpha-aminobutyric acid (S,S)-complexed structure defines a novel hydrogen-bonding site within the S2 pocket of calpains.
About this Structure
2NQG is a Single protein structure of sequence from Rattus norvegicus. Full crystallographic information is available from OCA.
Reference
Development of calpain-specific inactivators by screening of positional scanning epoxide libraries., Cuerrier D, Moldoveanu T, Campbell RL, Kelly J, Yoruk B, Verhelst SH, Greenbaum D, Bogyo M, Davies PL, J Biol Chem. 2007 Mar 30;282(13):9600-11. Epub 2007 Jan 11. PMID:17218315
Page seeded by OCA on Mon Mar 31 04:06:48 2008
