1sdx

Crystal structure of the zinc saturated C-terminal half of bovine lactoferrin at 2.0 A resolution reveals two additional zinc binding sites

spinqualitylabelsall models 1sdx, resolution 2.06Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 1sdx is a 2 chain structure with sequence from Bos taurus. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 2.06Å Ligands: BMA, CO3, MAN, NAG, NDG, SO4, ZN Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function TRFL_BOVIN Transferrins are iron binding transport proteins which can bind two Fe(3+) ions in association with the binding of an anion, usually bicarbonate. Lactotransferrin has antimicrobial activity. The most effective inhibitory activity was seen against E.coli and P.aeruginosa. Lactoferricin B is an antimicrobial peptide. Inhibits the growth of Gram-negative and Gram-positive bacteria. The lactotransferrin transferrin-like domain 1 functions as a serine protease of the peptidase S60 family that cuts arginine rich regions. This function contributes to the antimicrobial activity. 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 The crystal structure of the zinc-saturated C-terminal lobe of bovine lactoferrin has been determined at 2.0 A resolution using crystals stabilized at pH 3.8. This is the first metal-saturated structure of any functional lactoferrin at such a low pH. Purified samples of proteolytically generated zinc-saturated C-terminal lobe were crystallized from 0.1 M MES buffer pH 6.5 containing 25%(v/v) polyethyleneglycol monomethyl ether 550 and 0.1 M zinc sulfate heptahydrate. The crystals were transferred to 25 mM ammonium acetate buffer containing 25%(v/v) polyethyleneglycol monomethyl ether 550 and the pH was gradually changed from 6.5 to 3.8. The X-ray intensity data were collected with a 345 mm imaging-plate scanner mounted on an RU-300 rotating-anode X-ray generator using crystals soaked in the buffer at pH 3.8. The structure was determined with the molecular-replacement method using the coordinates of the monoferric C-terminal lobe of bovine lactoferrin as a search model and was refined to an R factor of 0.192 for all data to 2.0 A resolution. The final model comprises 2593 protein atoms (residues 342-676 and 681-685), 138 carbohydrate atoms (from 11 monosaccharide units in three glycan chains), three Zn2+ ions, one CO3(2-) ion, one SO(4)2- ions and 227 water molecules. The overall folding of the present structure is essentially similar to that of the monoferric C-terminal lobe of bovine lactoferrin, although it contains Zn2+ in place of Fe3+ in the metal-binding cleft as well as two additional Zn2+ ions on the surface of the C-terminal lobe. The Zn2+ ion in the cleft remains bound to the lobe with octahedral coordination. The bidentate carbonate ion is stabilized by a network of hydrogen bonds to Ala465, Gly466, Thr459 and Arg463. The other two zinc ions also form sixfold coordinations involving symmetry-related protein and water molecules. The number of monosaccharide residues from the three glycan chains of the C-terminal lobe was 11, which is the largest number observed to date. The structure shows that the C-terminal lobe of lactoferrin is capable of sequestering a Zn2+ ion at a pH of 3.8. This implies that the zinc ions can be sequestered over a wide pH range. The glycan chain attached to Asn545 may also have some influence on iron release from the C-terminal lobe. Structure of the zinc-saturated C-terminal lobe of bovine lactoferrin at 2.0 A resolution.,Jabeen T, Sharma S, Singh N, Bhushan A, Singh TP Acta Crystallogr D Biol Crystallogr. 2005 Aug;61(Pt 8):1107-15. Epub 2005, Jul 20. PMID:16041076 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Lactoferrin

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