2G8E

Calpain 1 proteolytic core in complex with SNJ-1715, a cyclic hemiacetal-type inhibitor

Summary for 2G8E

• Entry DOI: 10.2210/pdb2g8e/pdb
• Related: 1KXR 1TL9 1TLO 1ZCM 2G8J
• Descriptor: Calpain-1 catalytic subunit, CALCIUM ION, N-[(2S)-1,4-dihydroxybutan-2-yl]-N~2~-(phenylcarbamothioyl)-L-leucinamide, ... (5 entities in total)
• Functional Keywords: protease, peptidase, inhibitor, cyclic hemiacetal, aldehyde, hydrolase, hydrolase-hydrolase inhibitor complex, hydrolase/hydrolase inhibitor
• Biological source: Rattus norvegicus (Norway rat)
• Cellular location: Cytoplasm : P97571
• Total number of polymer chains: 1
• Total formula weight: 39433.42

Authors

Cuerrier, D.,Moldoveanu, T.,Davies, P.L.,Campbell, R.L. (deposition date: 2006-03-02, release date: 2006-06-06, Last modification date: 2023-08-30)

Primary citation

Cuerrier, D.,Moldoveanu, T.,Inoue, J.,Davies, P.L.,Campbell, R.L.
Calpain Inhibition by alpha-Ketoamide and Cyclic Hemiacetal Inhibitors Revealed by X-ray Crystallography
Biochemistry, 45:7446-7452, 2006

PubMed Abstract: Calpains are intracellular calcium-activated cysteine proteases whose unregulated proteolysis following the loss of calcium homeostasis can lead to acute degeneration during ischemic episodes and trauma, as well as Alzheimer's disease and cataract formation. The determination of the crystal structure of the proteolytic core of mu-calpain (muI-II) in a calcium-bound active conformation has made structure-guided design of active site inhibitors feasible. We present here high-resolution crystal structures of rat muI-II complexed with two reversible calpain-specific inhibitors employing cyclic hemiacetal (SNJ-1715) and alpha-ketoamide (SNJ-1945) chemistries that reveal new details about the interactions of inhibitors with this enzyme. The SNJ-1715 complex confirms that the free aldehyde is the reactive species of the cornea-permeable cyclic hemiacetal. The alpha-ketoamide warhead of SNJ-1945 binds with the hydroxyl group of the tetrahedral adduct pointing toward the catalytic histidine rather than the oxyanion hole. The muI-II-SNJ-1945 complex shows residue Glu261 displaced from the S1' site by the inhibitor, resulting in an extended "open" conformation of the domain II gating loop and an unobstructed S1' site. This conformation offers an additional template for structure-based drug design extending to the primed subsites. An important role for the highly conserved Glu261 is proposed.

PubMed: 16768440
DOI: 10.1021/bi060425j

Experimental method

X-RAY DIFFRACTION (2.25 Å)