Sandbox 125
From Proteopedia
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The PY-NLS of 2H4M contains a hydrophobic rather than a basic N-terminal motif. Hydrophobic interactions at the N-terminal motif of the PY-NLS include: | The PY-NLS of 2H4M contains a hydrophobic rather than a basic N-terminal motif. Hydrophobic interactions at the N-terminal motif of the PY-NLS include: | ||
- | <scene name='37/372725/Kapb2_hydrophobic_interactions/4'>Phe273, Gly274, Pro275 and Met276 of the NLS with Trp730 and Ile773 of KapB2</scene>. Interactions of the C-terminal RX2-5PY motif of the NLS include: <scene name='37/372725/Kapb2_hydrophobic_interactions/6'>Arg284 of the NLS with Glu509 and Asp543 of KapB2.</scene>; <scene name='37/372725/Kapb2_hydrophobic_interactions/ | + | <scene name='37/372725/Kapb2_hydrophobic_interactions/4'>Phe273, Gly274, Pro275 and Met276 of the NLS with Trp730 and Ile773 of KapB2</scene>. Interactions of the C-terminal RX2-5PY motif of the NLS include: <scene name='37/372725/Kapb2_hydrophobic_interactions/6'>Arg284 of the NLS with Glu509 and Asp543 of KapB2.</scene>; <scene name='37/372725/Kapb2_hydrophobic_interactions/9'>Pro288 and Tyr289 of the NLS with Ala380, Ala381, Asp384, Leu419, Ile457, Trp460 and Arg464 of KapB2.</scene> |
Upon binding Kapβ2,the NLS gains structure, conforms to and makes contact with the internal surface of the KapB2 C-terminal arch. | Upon binding Kapβ2,the NLS gains structure, conforms to and makes contact with the internal surface of the KapB2 C-terminal arch. |
Revision as of 21:54, 2 January 2014
Introduction
Karyopherin Beta 2 (Kapβ2) is an importin that transports various cargo proteins into the nucleus through interactions with nucleoporins, which are proteins of the nuclear pore complex (NPC). One might overlook the significance of this protein but it actually plays a crucial role in the human body by mediating transport of RNA-binding proteins involved in Transcription and RNA Processing, RNA transport and translation. The structure of Kapβ2 is composed of 20 antiparallel helices called HEAT repeats. These HEAT repeats contribute to Kapβ2’s large superhelical shape. The protein is shown to form two arches: one at the N-terminal and the other at the C-terminal. Through recognition of a nuclear localization signal (NLS) located on its cargo, Kapβ2 binds to its cargo via its C-terminal arch. Release of the cargo is mediated by RanGTP, which once bound, leads to a large movement of the 62-residue heat repeat 8 loop into the C-terminal arch. This conformational change results in the dissociation of the cargo as the b2 loop binds the NLS binding site.
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