Glutamine Phosphoribosylpyrophosphate, subunit 1, domain 1
Structural features of 26S and 20S proteasomes.
Molecular structure of 20S and 26S proteasomes.
Structure and function of the 20S proteasome and of its regulatory complexes.
Catalytic mechanism of the 20S proteasome of Thermoplasma acidophilum revealed by X-ray crystallography.
The proteasome from Thermoplasma acidophilum is neither a cysteine nor a serine protease.
Structural features of archaebacterial and eukaryotic proteasomes.
A protein catalytic framework with an N-terminal nucleophile is capable of self-activation.
Functions of the proteasome: the lysis at the end of the tunnel.
Crystal structure of the 20S proteasome from the archaeon T. acidophilum at 3.4 A resolution.
Proteasome from Thermoplasma acidophilum: a threonine protease.
Proteasome: a complex protease with a new fold and a distinct mechanism.
Structure and functions of the 20S and 26S proteasomes.
Autocatalytic processing of the 20S proteasome.
Synthesis, kinetic characterization and X-ray analysis of peptide aldehydes as inhibitors of the 20S proteasomes from Thermoplasma acidophilum and Saccharomyces cerevisiae.
Active site-directed inhibitors of Rhodococcus 20 S proteasome. Kinetics and mechanism.
Catalytic activities of the 20 S proteasome, a multicatalytic proteinase complex.
Proteasomes in the archaea: from structure to function.
Why does threonine, and not serine, function as the active site nucleophile in proteasomes?
Conservation of substructures in proteins: interfaces of secondary structural elements in proteasomal subunits.
The 11S regulators of 20S proteasome activity.
Stabilization signals: a novel regulatory mechanism in the ubiquitin/proteasome system.
The pore of activated 20S proteasomes has an ordered 7-fold symmetric conformation.
Investigations on the maturation and regulation of archaebacterial proteasomes.
The 1.9 A structure of a proteasome-11S activator complex and implications for proteasome-PAN/PA700 interactions.
This enzyme was transferred from E.C. 3.4.99.46 to E.C. 3.4.25.1. The structure of this enzyme is cylindrical with four layers of seven subunits, composed of two different subunits, alpha and beta. All the alpha subunits are enzymatically inactive, whereas the beta-subunits exhibit proteolytic activity. Alpha- and beta-subunits belong to peptidase family-T1A and -T1B, respectively. According to the literature [18], this enzyme has got a similar mechanism to that of its counterpart in yeast (M00123 in EzCatDB). (1) Alpha-amino group of Thr1 acts as a general base to activate the nucleophile, sidechain of Thr1, through a water molecule (NUK). At the same time, Lys33, which is modulated by Glu17, might modulate or stabilize the nucleophilicity of Thr1. (2) Thr1 makes a nucleophilic attack on the carbonyl carbon of the target peptide bond, forming a tetrahedral (hemiacetal) transition-state. (3) The alpha-amino group of Thr1 acts as a general acid to protonate the leaving group, giving a carbonyl intermediate through a water. The intermediate might be stabilized by an oxyanion hole, composed of the sidechain of Lys33 and mainchain amide of Gly47. (4) Alpha-amino group of Thr1 acts as a general base to activate the NUK water, through another water, which completes hydrolysis. ### Autocatalysis, in which Thr1 acts as a nucleophile and Ser129 forms an oxyanion hole, activates the catalytic site of this enzyme (see [14]).