2bku: Difference between revisions
From Proteopedia
Jump to navigationJump to search
No edit summary |
No edit summary |
||
| Line 5: | Line 5: | ||
==Overview== | ==Overview== | ||
Nuclear protein import is mediated mainly by the transport factor, importin-beta that binds cytoplasmic cargo, most often via the, importin-alpha adaptor, and then transports it through nuclear pore, complexes. This active transport is driven by disassembly of the import, complex by nuclear RanGTP. The switch I and II loops of Ran change, conformation with nucleotide state, and regulate its interactions with, nuclear trafficking components. Importin-beta consists of 19 HEAT repeats, that are based on a pair of antiparallel alpha-helices (referred to as the, A- and B-helices). The HEAT repeats stack to yield two C-shaped arches, linked together to form a helicoidal molecule that has considerable, conformational flexibility. Here we present the structure of full-length, yeast importin-beta ... | Nuclear protein import is mediated mainly by the transport factor, importin-beta that binds cytoplasmic cargo, most often via the, importin-alpha adaptor, and then transports it through nuclear pore, complexes. This active transport is driven by disassembly of the import, complex by nuclear RanGTP. The switch I and II loops of Ran change, conformation with nucleotide state, and regulate its interactions with, nuclear trafficking components. Importin-beta consists of 19 HEAT repeats, that are based on a pair of antiparallel alpha-helices (referred to as the, A- and B-helices). The HEAT repeats stack to yield two C-shaped arches, linked together to form a helicoidal molecule that has considerable, conformational flexibility. Here we present the structure of full-length, yeast importin-beta (Kap95p or karyopherin-beta) complexed with RanGTP, which provides a basis for understanding the crucial cargo-release step of, nuclear import. We identify a key interaction site where the RanGTP switch, I loop binds to the carboxy-terminal arch of Kap95p. This interaction, produces a change in helicoidal pitch that locks Kap95p in a conformation, that cannot bind importin-alpha or cargo. We suggest an allosteric, mechanism for nuclear import complex disassembly by RanGTP. | ||
==About this Structure== | ==About this Structure== | ||
2BKU is a | 2BKU is a [http://en.wikipedia.org/wiki/Protein_complex Protein complex] structure of sequences from [http://en.wikipedia.org/wiki/Canis_lupus_familiaris Canis lupus familiaris] and [http://en.wikipedia.org/wiki/Saccharomyces_cerevisiae Saccharomyces cerevisiae] with MG and GTP as [http://en.wikipedia.org/wiki/ligands ligands]. The following page contains interesting information on the relation of 2BKU with [[http://pdb.rcsb.org/pdb/static.do?p=education_discussion/molecule_of_the_month/pdb85_1.html Importins]]. Structure known Active Site: AC1. Full crystallographic information is available from [http://ispc.weizmann.ac.il/oca-bin/ocashort?id=2BKU OCA]. | ||
==Reference== | ==Reference== | ||
| Line 28: | Line 28: | ||
[[Category: rangtp]] | [[Category: rangtp]] | ||
''Page seeded by [http://ispc.weizmann.ac.il/oca OCA ] on | ''Page seeded by [http://ispc.weizmann.ac.il/oca OCA ] on Mon Nov 5 15:13:27 2007'' | ||
