1cb6

STRUCTURE OF HUMAN APOLACTOFERRIN AT 2.0 A RESOLUTION.

spinqualitylabelsall models 1cb6, resolution 2.00Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 1cb6 is a 1 chain structure with sequence from Homo sapiens. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Ligands: CL Resources: FirstGlance, OCA, RCSB, PDBsum 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 three-dimensional structure of a form of human apolactoferrin, in which one lobe (the N-lobe) has an open conformation and the other lobe (the C-lobe) is closed, has been refined at 2.0 A resolution. The refinement, by restrained least-squares methods, used synchrotron radiation X-ray diffraction data combined with a lower resolution diffractometer data set. The final refined model (5346 protein atoms from residues 1-691, two Cl- ions and 363 water molecules) gives a crystallographic R factor of 0.201 (Rfree = 0. 286) for all 51305 reflections in the resolution range 10.0-2.0 A. The conformational change in the N-lobe, which opens up the binding cleft, involves a 54 degrees rotation of the N2 domain relative to the N1 domain. This also results in a small reorientation of the two lobes relative to one another with a further approximately 730 A2 of surface area being buried as the N2 domain contacts the C-lobe and the inter-lobe helix. These new contacts also involve the C-terminal helix and provide a mechanism through which the conformational and iron-binding status of the N-lobe can be signalled to the C-lobe. Surface-area calculations indicate a fine balance between open and closed forms of lactoferrin, which both have essentially the same solvent-accessible surface. Chloride ions are bound in the anion-binding sites of both lobes, emphasizing the functional significance of these sites. The closed configuration of the C-lobe, attributed in part to weak stabilization by crystal packing interactions, has important implications for lactoferrin dynamics. It shows that a stable closed structure, essentially identical to that of the iron-bound form, can be formed in the absence of iron binding. Structure of human apolactoferrin at 2.0 A resolution. Refinement and analysis of ligand-induced conformational change.,Jameson GB, Anderson BF, Norris GE, Thomas DH, Baker EN Acta Crystallogr D Biol Crystallogr. 1998 Nov 1;54(Pt 6 Pt 2):1319-35. PMID:10089508 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Lactoferrin

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