1j1y

Crystal Structure of PaaI from Thermus thermophilus HB8

spinqualitylabelsall models 1j1y, resolution 1.70Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 1j1y is a 2 chain structure with sequence from Thermus thermophilus HB8. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 1.7Å Ligands: CL, MG Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT, TOPSAN Function Q5SJP3_THET8 Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMed Hot dog fold proteins sharing the characteristic "hot dog" fold are known to involve certain coenzyme A binding enzymes with various oligomeric states. In order to elucidate the oligomerization-function relationship of the hot dog fold proteins, crystal structures of the phenylacetate degradation protein PaaI from Thermus thermophilus HB8 (TtPaaI), a tetrameric acyl-CoA thioesterase with the hot dog fold, have been determined and compared with those of other family members. In the liganded crystal forms with coenzyme A derivatives, only two of four intersubunit catalytic pockets of the TtPaaI tetramer are occupied by the ligands. A detailed structural comparison between several liganded and unliganded forms reveals that a subtle rigid-body rearrangement of subunits within 2 degrees upon binding of the first two ligand molecules can induce a strict negative cooperativity to prevent further binding at the remaining two pockets, indicating that the so-called "half-of-the-sites reactivity" of oligomeric enzymes is visualized for the first time. Considering kinetic and mutational analyses together, a possible reaction mechanism of TtPaaI is proposed; one tetramer binds only two acyl-CoA molecules with a novel asymmetric induced-fit mechanism and carries out the hydrolysis according to a base-catalyzed reaction through activation of a water molecule by Asp48. From a structural comparison with other family members, it is concluded that a subgroup of the hot dog fold protein family, referred to as "asymmetric hot dog thioesterases" including medium chain acyl-CoA thioesterase II from Escherichia coli and human thioesterase III, might share the same oligomerization mode and the asymmetric induced-fit mechanism as observed in TtPaaI. A novel induced-fit reaction mechanism of asymmetric hot dog thioesterase PAAI.,Kunishima N, Asada Y, Sugahara M, Ishijima J, Nodake Y, Sugahara M, Miyano M, Kuramitsu S, Yokoyama S, Sugahara M J Mol Biol. 2005 Sep 9;352(1):212-28. PMID:16061252 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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