4xan

Carboplatin binding to HEWL in NaBr crystallisation conditions studied at an X-ray wavelength of 0.9163A

spinqualitylabelsall models 4xan, resolution 1.47Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 4xan is a 1 chain structure with sequence from Gallus gallus. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Ligands: ACT, BR, DMS, NA, QPT Related: 4nsf Activity: Lysozyme, with EC number 3.2.1.17 Resources: FirstGlance, OCA, RCSB, PDBsum Function [LYSC_CHICK] Lysozymes have primarily a bacteriolytic function; those in tissues and body fluids are associated with the monocyte-macrophage system and enhance the activity of immunoagents. Has bacteriolytic activity against M.luteus. Publication Abstract from PubMed Carboplatin is a second-generation platinum anticancer agent used for the treatment of a variety of cancers. Previous X-ray crystallographic studies of carboplatin binding to histidine (in hen egg-white lysozyme; HEWL) showed the partial conversion of carboplatin to cisplatin owing to the high NaCl concentration used in the crystallization conditions. HEWL co-crystallizations with carboplatin in NaBr conditions have now been carried out to confirm whether carboplatin converts to the bromine form and whether this takes place in a similar way to the partial conversion of carboplatin to cisplatin observed previously in NaCl conditions. Here, it is reported that a partial chemical transformation takes place but to a transplatin form. Thus, to attempt to resolve purely carboplatin binding at histidine, this study utilized co-crystallization of HEWL with carboplatin without NaCl to eliminate the partial chemical conversion of carboplatin. Tetragonal HEWL crystals co-crystallized with carboplatin were successfully obtained in four different conditions, each at a different pH value. The structural results obtained show carboplatin bound to either one or both of the N atoms of His15 of HEWL, and this particular variation was dependent on the concentration of anions in the crystallization mixture and the elapsed time, as well as the pH used. The structural details of the bound carboplatin molecule also differed between them. Overall, the most detailed crystal structure showed the majority of the carboplatin atoms bound to the platinum centre; however, the four-carbon ring structure of the cyclobutanedicarboxylate moiety (CBDC) remained elusive. The potential impact of the results for the administration of carboplatin as an anticancer agent are described. Carboplatin binding to histidine.,Tanley SW, Diederichs K, Kroon-Batenburg LM, Levy C, Schreurs AM, Helliwell JR Acta Crystallogr F Struct Biol Commun. 2014 Sep 1;70(Pt 9):1135-42. doi:, 10.1107/S2053230X14016161. Epub 2014 Aug 29. PMID:25195881 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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