Integrative Structure Determination of the Components of the Nuclear Pore Complex by X-ray Crystallography, Small Angle X-Ray Scattering, Electron Microscopy, NMR and Comparative Modeling
소속 :
연사 : Seung Joong Kim (University of California)
일시 : 2011-09-06 16:00 ~
장소 : 23동 417호
일 시 : 2011년 9월 6일, 4:00 PM
장 소 : 23동 417호
-Abstract-
The Nuclear Pore Complex (NPC, ~50 MDa) is the sole passageway for the transport of
macromolecules across the nuclear envelope. The NPC plays a key role in numerous critical
cellular processes such as transcription, and many of its components are implicated in human
diseases such as cancer. Previous work (ref 1, 2) defined the relative positions of its 456
constituent proteins (nucleoporin or Nups), based on spatial restraints derived from biophysical,
electron microscopy, and proteomic data. Further elucidation of the evolutionary origin, transport
mechanism, and assembly of the NPC will require higher resolution information. As part of an
effort to improve upon the resolution and accuracy of the NPC structure, we set out to determine
the atomic structures of the NPC components. Because it proved difficult to determine the
atomic structures of whole Nups by X-ray crystallography alone, we are relying on multiple
datasets that are combined computationally by our Integrative Modeling Platform (IMP) package
(http://salilab.org/imp). In particular, we developed an integrative modeling approach that
benefits from crystallographic structures of fragments of the protein or its homologs, Solution
Small Angle X-ray Scattering (SAXS) profiles of the protein and its fragments (ref 3), NMR, and
negative stain Electron Microscopy (EM) micrographs of the protein. Each dataset is converted
into a set of spatial restraints on the protein structure, followed by finding a model that satisfies
the restraints as well as possible using a Monte Carlo / molecular dynamics optimization
procedure. The approach will be illustrated by its application to yeast Nup133.
장 소 : 23동 417호
-Abstract-
The Nuclear Pore Complex (NPC, ~50 MDa) is the sole passageway for the transport of
macromolecules across the nuclear envelope. The NPC plays a key role in numerous critical
cellular processes such as transcription, and many of its components are implicated in human
diseases such as cancer. Previous work (ref 1, 2) defined the relative positions of its 456
constituent proteins (nucleoporin or Nups), based on spatial restraints derived from biophysical,
electron microscopy, and proteomic data. Further elucidation of the evolutionary origin, transport
mechanism, and assembly of the NPC will require higher resolution information. As part of an
effort to improve upon the resolution and accuracy of the NPC structure, we set out to determine
the atomic structures of the NPC components. Because it proved difficult to determine the
atomic structures of whole Nups by X-ray crystallography alone, we are relying on multiple
datasets that are combined computationally by our Integrative Modeling Platform (IMP) package
(http://salilab.org/imp). In particular, we developed an integrative modeling approach that
benefits from crystallographic structures of fragments of the protein or its homologs, Solution
Small Angle X-ray Scattering (SAXS) profiles of the protein and its fragments (ref 3), NMR, and
negative stain Electron Microscopy (EM) micrographs of the protein. Each dataset is converted
into a set of spatial restraints on the protein structure, followed by finding a model that satisfies
the restraints as well as possible using a Monte Carlo / molecular dynamics optimization
procedure. The approach will be illustrated by its application to yeast Nup133.
