7dn7 | pdb_00007dn7

Crystal structure of ternary complexes of lactoperoxidase with hydrogen peroxide at 1.70 A resolution

spinqualitylabelsall models 7dn7, resolution 1.70Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 7dn7 is a 1 chain structure with sequence from Bos taurus. This structure supersedes the now removed PDB entries 6laq and 3ql6. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Ligands: CA, EDO, HEM, IOD, NAG, OSM, PEO, ZN Activity: Peroxidase, with EC number 1.11.1.7 Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function [PERL_BOVIN] LPO is an antimicrobial agent. It is thought to help protect the udder from infection and promote growth in newborn calves. Publication Abstract from PubMed Lactoperoxidase (LPO) is a mammalian heme peroxidase which catalyzes the conversion of thiocyanate (SCN ) and iodide (I(-)) by hydrogen peroxide (H2O2) into antimicrobial hypothiocyanite (OSCN ) and hypoiodite (IO(-)). The prosthetic heme group is covalently attached to LPO through two ester linkages involving conserved glutamate and aspartate residues. On the proximal side, His351 is coordinated to heme iron while His 109 is located in the substrate binding site on the distal heme side. We report here the first structure of the ternary complex of LPO with iodide (I(-)) and H2O2 at 1.77 A resolution. LPO was crystallized with ammonium iodide and the crystals were soaked in the reservoir solution containing H2O2. Structure determination showed the presence of an iodide ion and a H2O2 molecule in the substrate binding site. The iodide ion occupied the position which is stabilized by the interactions with heme moiety, His109, Arg255 and Glu258 while H2O2 was held between the heme iron and His109. The presence of I(-) in the distal heme cavity seems to screen the positive charge of Arg255 thus suppressing the proton transfer from H2O2 to His109. This prevents compound I formation and allows trapping of a stable enzyme-substrate (LPO-I(-)-H2O2) ternary complex. This stable geometrical arrangement of H2O2 in the distal heme cavity of LPO is similar to that of H2O2 in the structure of the transient intermediate of the palm tree heme peroxidase. The biochemical studies showed that the catalytic activity of LPO decreased when the samples of LPO were preincubated with ammonium iodide. Structure of a ternary complex of lactoperoxidase with iodide and hydrogen peroxide at 1.77 A resolution.,Singh PK, Sharma P, Bhushan A, Kaur P, Sharma S, Singh TP J Inorg Biochem. 2021 Apr 18;220:111461. doi: 10.1016/j.jinorgbio.2021.111461. PMID:33882424 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Lactoperoxidase

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