1qma | pdb_00001qma
NUCLEAR TRANSPORT FACTOR 2 (NTF2) W7A MUTANT
Structural highlights
Function[NTF2_HUMAN] Facilitates protein transport into the nucleus. Interacts with the nucleoporin p62 and with Ran. Acts at a relatively late stage of nuclear protein import, subsequent to the initial docking of nuclear import ligand at the nuclear envelope. Could be part of a multicomponent system of cytosolic factors that assemble at the pore complex during nuclear import. 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 PubMedNuclear transport factor 2 (NTF2) is a small, homodimeric protein that binds to both RanGDP and xFxFG repeat-containing nucleoporins, such as yeast Nsp1p and vertebrate p62. NTF2 is required for efficient nuclear protein import and has been shown to mediate the nuclear import of RanGDP. We have used the crystal structures of rat NTF2 and its complex with RanGDP to design a mutant, W7A-NTF2, in which the affinity for xFxFG-repeat nucleoporins is reduced while wild-type binding to RanGDP is retained. The 2.5 A resolution crystal structure of W7A-NTF2 is virtually superimposable upon the wild-type protein structure, indicating that the mutation had not introduced a more general conformational change. Therefore, our data suggest that the exposed side-chain of residue 7 is crucial to the interaction between NTF2 and xFxFG repeat-containing nucleoporins. Consistent with its reduced affinity for xFxFG nucleoporins, fluorescently labelled W7A-NTF2 binds less strongly to the nuclear envelope of permeabilized cultured cells than wild-type NTF2 and, when microinjected into Xenopus oocytes, colloidal gold coated with W7A-NTF2 binds less strongly to the central channel of nuclear pore complexes than wild-type NTF2-coated gold. Significantly, W7A-NTF2 only weakly stimulated the nuclear import of fluorescein-labelled RanGDP, providing direct evidence that an interaction between NTF2 and xFxFG repeat-containing nucleoporins is required to mediate the nuclear import of RanGDP. Interaction between NTF2 and xFxFG-containing nucleoporins is required to mediate nuclear import of RanGDP.,Bayliss R, Ribbeck K, Akin D, Kent HM, Feldherr CM, Gorlich D, Stewart M J Mol Biol. 1999 Oct 29;293(3):579-93. PMID:10543952[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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