title: The structure of SecB/OmpA as visualized by electron microscopy: The mature region of the precursor protein binds asymmetrically to SecB.
abstract: SecB, a molecular chaperone in Escherichia coli, binds a subset of precursor proteins that are exported across the plasma membrane via the Sec pathway. Previous studies showed that SecB bound directly to the mature region rather than to the signal sequence of the precursor protein. To determine the binding pattern of SecB and the mature region of the preprotein, here, we visualized the structure of the SecB/OmpA complex by electron microscopy. This complex is composed by two parts: the main density represents one SecB tetramer and the unfolded part of OmpA wrapping round it; the elongated smaller density represents the rest of OmpA. Each SecB protomer makes a different contribution to the binding of SecB with OmpA. The binding pattern between SecB tetramer and OmpA is asymmetric.
authors.affiliation: State-Key Laboratory of Biomembrane and Membrane Biotechnology, Center for Structural Biology, School of Life Science, Tsinghua University, Beijing 100084, China.
authors.forename: Ying
authors.initials: Y
authors.lastname: Tang
authors.forename: Xijiang
authors.initials: X
authors.lastname: Pan
authors.forename: Phang C
authors.initials: PC
authors.lastname: Tai
authors.forename: Sen-Fang
authors.initials: SF
authors.lastname: Sui
mesh_terms: D001425:Bacterial Outer Membrane Proteins / Q000737:chemistry* / Q000648:ultrastructure; D001426:Bacterial Proteins / Q000737:chemistry* / Q000648:ultrastructure; D004926:Escherichia coli / Q000378:metabolism*; D008854:Microscopy, Electron; D011487:Protein Conformation
chemical_list: D001425:Bacterial Outer Membrane Proteins; D001426:Bacterial Proteins; C057842:SecB protein, Bacteria; C078167:OMPA outer membrane proteins