On the basis of the structure of a HslUV complex, a mechanism of allosteric activation of the HslV protease, wherein binding of the HslU chaperone propagates a conformational change to the active site cleft of the protease, has been proposed. Here, the 3 ...
On the basis of the structure of a HslUV complex, a mechanism of allosteric activation of the HslV protease, wherein binding of the HslU chaperone propagates a conformational change to the active site cleft of the protease, has been proposed. Here, the 3.1 A X-ray crystallographic structure of Haemophilus influenzae HslUV complexed with a vinyl sulfone inhibitor is described. The inhibitor, which reacts to form a covalent linkage to Thr1 of HslV, binds in an "antiparallel beta" manner, with hydrogen-bond interactions between the peptide backbone of the protease and that of the inhibitor, and with two leucinyl side chains of the inhibitor binding in the S1 and S3 specificity pockets of the protease. Comparison of the structure of the HslUV-inhibitor complex with that of HslV without inhibitor and in the absence of HslU reveals that backbone interactions would correctly position a substrate for cleavage in the HslUV complex, but not in the HslV protease alone, corroborating the proposed mechanism of allosteric activation. This activation mechanism differs from that of the eukaryotic proteasome, for which binding of activators opens a gated channel that controls access of substrates to the protease, but does not perturb the active site environment.
Related Citations:
Crystal and Solution Structures of an HslUV Protease-Chaperone Complex Sousa, M.C., Trame, C.B., Tsuruta, H., Wilbanks, S.M., Reddy, V.S., McKay, D.B. (2000) Cell 103: 633
Structure of Haemophilus influenzae HslV protein at 1.9 A resolution, revealing a cation-binding site near the catalytic site Sousa, M.C., McKay, D.B. (2001) Acta Crystallogr D Biol Crystallogr 57: 1950
Structure of Haemophilus influenzae HslU protein in crystals with one-dimensional disorder twinning Trame, C.B., McKay, D.B. (2001) Acta Crystallogr D Biol Crystallogr 57: 1079
Organizational Affiliation:
Department of Structural Biology, Stanford University School of Medicine, Sherman Fairchild Building, Stanford, CA 94305-5400, USA.
EA [auth G] FA [auth H] GA [auth I] HA [auth J] IA [auth K]
EA [auth G], FA [auth H], GA [auth I], HA [auth J], IA [auth K], JA [auth L], KA [auth M], LA [auth N], MA [auth O], NA [auth P], OA [auth Q], PA [auth R]
4-IODO-3-NITROPHENYL ACETYL-LEUCINYL-LEUCINYL-LEUCINYL-VINYLSULFONE C28 H43 I N4 O8 S RSYTXXARKSZDKY-PUHATCMVSA-N
AA [auth C] BA [auth D] CA [auth E] DA [auth F] QA [auth S]
AA [auth C], BA [auth D], CA [auth E], DA [auth F], QA [auth S], RA [auth T], SA [auth U], TA [auth V], UA [auth W], VA [auth X], Y [auth A], Z [auth B]
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