6y2k | pdb_00006y2k

Crystal structure of beta-galactosidase from the psychrophilic Marinomonas ef1

spinqualitylabelsall models 6y2k, resolution 1.90Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 6y2k is a 1 chain structure with sequence from Marinomonas sp. ef1. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 1.9Å Ligands: CL, GOL Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Publication Abstract from PubMed To survive in cold environments, psychrophilic organisms produce enzymes endowed with high specific activity at low temperature. The structure of these enzymes is usually flexible and mostly thermolabile. In this work, we investigate the structural basis of cold adaptation of a GH42 beta-galactosidase from the psychrophilic Marinomonas ef1. This enzyme couples cold activity with astonishing robustness for a psychrophilic protein, for it retains 23% of its highest activity at 5 degrees C and it is stable for several days at 37 degrees C and even 50 degrees C. Phylogenetic analyses indicate a close relationship with thermophilic beta-galactosidases, suggesting that the present-day enzyme evolved from a thermostable scaffold modeled by environmental selective pressure. The crystallographic structure reveals the overall similarity with GH42 enzymes, along with a hexameric arrangement (dimer of trimers) not found in psychrophilic, mesophilic and thermophilic homologues. In the quaternary structure, protomers form a large central cavity, whose accessibility to the substrate is promoted by the dynamic behavior of surface loops, even at low temperature. This peculiar temperature-driven cooperative behavior of the enzyme is likely related to the increase of the internal cavity permeability triggered by heating. Overall, our results highlight a novel strategy of enzyme cold adaptation, based on the oligomerization state of the enzyme, which effectively challenges the paradigm of cold activity coupled with intrinsic thermolability. The co-existence of cold activity and thermal stability in an Antarctic GH42 beta-galactosidase relies on its hexametric quaternary arrangement.,Mangiagalli M, Lapi M, Maione S, Orlando M, Brocca S, Pesce A, Barbiroli A, Camilloni C, Pucciarelli S, Lotti M, Nardini M FEBS J. 2020 May 4. doi: 10.1111/febs.15354. PMID:32363751 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Galactosidase 3D structures

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