1
|
M13 Procoat Protein Insertion into YidC and SecYEG Proteoliposomes and Liposomes. J Mol Biol 2011; 406:362-70. [DOI: 10.1016/j.jmb.2010.12.036] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2010] [Revised: 12/22/2010] [Accepted: 12/23/2010] [Indexed: 11/21/2022]
|
2
|
|
3
|
Karamanou S, Gouridis G, Papanikou E, Sianidis G, Gelis I, Keramisanou D, Vrontou E, Kalodimos CG, Economou A. Preprotein-controlled catalysis in the helicase motor of SecA. EMBO J 2007; 26:2904-14. [PMID: 17525736 PMCID: PMC1894763 DOI: 10.1038/sj.emboj.7601721] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2007] [Accepted: 04/17/2007] [Indexed: 11/08/2022] Open
Abstract
The cornerstone of the functionality of almost all motor proteins is the regulation of their activity by binding interactions with their respective substrates. In most cases, the underlying mechanism of this regulation remains unknown. Here, we reveal a novel mechanism used by secretory preproteins to control the catalytic cycle of the helicase 'DEAD' motor of SecA, the preprotein translocase ATPase. The central feature of this mechanism is a highly conserved salt-bridge, Gate1, that controls the opening/closure of the nucleotide cleft. Gate1 regulates the propagation of binding signal generated at the Preprotein Binding Domain to the nucleotide cleft, thus allowing the physical coupling of preprotein binding and release to the ATPase cycle. This relay mechanism is at play only after SecA has been previously 'primed' by binding to SecYEG, the transmembrane protein-conducting channel. The Gate1-controlled relay mechanism is essential for protein translocase catalysis and may be common in helicase motors.
Collapse
Affiliation(s)
- Spyridoula Karamanou
- Institute of Molecular Biology and Biotechnology, Foundation of Research and Technology-Hellas, Crete, Greece
| | - Giorgos Gouridis
- Institute of Molecular Biology and Biotechnology, Foundation of Research and Technology-Hellas, Crete, Greece
- Department of Biology, University of Crete, Crete, Greece
| | - Efrosyni Papanikou
- Institute of Molecular Biology and Biotechnology, Foundation of Research and Technology-Hellas, Crete, Greece
| | - Giorgos Sianidis
- Institute of Molecular Biology and Biotechnology, Foundation of Research and Technology-Hellas, Crete, Greece
| | - Ioannis Gelis
- Department of Chemistry, Rutgers University, Newark, NJ, USA
| | | | - Eleftheria Vrontou
- Institute of Molecular Biology and Biotechnology, Foundation of Research and Technology-Hellas, Crete, Greece
- Department of Biology, University of Crete, Crete, Greece
| | | | - Anastassios Economou
- Institute of Molecular Biology and Biotechnology, Foundation of Research and Technology-Hellas, Crete, Greece
- Department of Biology, University of Crete, Crete, Greece
- Institute of Molecular Biology and Biotechnology, University of Crete, PO Box 1385, 71110 Iraklio, Crete, Greece. Tel.: +30 2810 391166/391167; Fax: +30 2810 391166; E-mail:
| |
Collapse
|
4
|
Abstract
We identified 1113 articles (103 reviews, 1010 primary research articles) published in 2005 that describe experiments performed using commercially available optical biosensors. While this number of publications is impressive, we find that the quality of the biosensor work in these articles is often pretty poor. It is a little disappointing that there appears to be only a small set of researchers who know how to properly perform, analyze, and present biosensor data. To help focus the field, we spotlight work published by 10 research groups that exemplify the quality of data one should expect to see from a biosensor experiment. Also, in an effort to raise awareness of the common problems in the biosensor field, we provide side-by-side examples of good and bad data sets from the 2005 literature.
Collapse
Affiliation(s)
- Rebecca L Rich
- Center for Biomolecular Interaction Analysis, University of Utah, Salt Lake City, UT 84132, USA
| | | |
Collapse
|
5
|
Papanikou E, Karamanou S, Baud C, Frank M, Sianidis G, Keramisanou D, Kalodimos CG, Kuhn A, Economou A. Identification of the Preprotein Binding Domain of SecA. J Biol Chem 2005; 280:43209-17. [PMID: 16243836 DOI: 10.1074/jbc.m509990200] [Citation(s) in RCA: 69] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
SecA, the preprotein translocase ATPase, has a helicase DEAD motor. To catalyze protein translocation, SecA possesses two additional flexible domains absent from other helicases. Here we demonstrate that one of these "specificity domains" is a preprotein binding domain (PBD). PBD is essential for viability and protein translocation. PBD mutations do not abrogate the basal enzymatic properties of SecA (nucleotide binding and hydrolysis), nor do they prevent SecA binding to the SecYEG protein conducting channel. However, SecA PBD mutants fail to load preproteins onto SecYEG, and their translocation ATPase activity does not become stimulated by preproteins. Bulb and Stem, the two sterically proximal PBD substructures, are physically separable and have distinct roles. Stem binds signal peptides, whereas the Bulb binds mature preprotein regions as short as 25 amino acids. Binding of signal or mature region peptides or full-length preproteins causes distinct conformational changes to PBD and to the DEAD motor. We propose that (a) PBD is a preprotein receptor and a physical bridge connecting bound preproteins to the DEAD motor, and (b) preproteins control the ATPase cycle via PBD.
Collapse
Affiliation(s)
- Efrosyni Papanikou
- Institute of Molecular Biology and Biotechnology, F.O.R.T.H., University of Crete, P.O. Box 1527, GR-711 10 Iraklio, Crete, Greece
| | | | | | | | | | | | | | | | | |
Collapse
|
6
|
Chou YT, Gierasch LM. The Conformation of a Signal Peptide Bound by Escherichia coli Preprotein Translocase SecA. J Biol Chem 2005; 280:32753-60. [PMID: 16046390 DOI: 10.1074/jbc.m507532200] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
To understand the structural nature of signal sequence recognition by the preprotein translocase SecA, we have characterized the interactions of a signal peptide corresponding to a LamB signal sequence (modified to enhance aqueous solubility) with SecA by NMR methods. One-dimensional NMR studies showed that the signal peptide binds SecA with a moderately fast exchange rate (Kd approximately 10(-5) m). The line-broadening effects observed from one-dimensional and two-dimensional NMR spectra indicated that the binding mode does not equally immobilize all segments of this peptide. The positively charged arginine residues of the n-region and the hydrophobic residues of the h-region had less mobility than the polar residues of the c-region in the SecA-bound state, suggesting that this peptide has both electrostatic and hydrophobic interactions with the binding pocket of SecA. Transferred nuclear Overhauser experiments revealed that the h-region and part of the c-region of the signal peptide form an alpha-helical conformation upon binding to SecA. One side of the hydrophobic core of the helical h-region appeared to be more strongly bound in the binding pocket, whereas the extreme C terminus of the peptide was not intimately involved. These results argue that the positive charges at the n-region and the hydrophobic helical h-region are the selective features for recognition of signal sequences by SecA and that the signal peptide-binding site on SecA is not fully buried within its structure.
Collapse
Affiliation(s)
- Yi-Te Chou
- Department of Chemistry, University of Massachusetts, Amherst, Massachusetts 01003-04510, USA
| | | |
Collapse
|