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Biochemistry, Biophysics, and Structural Biology Commons

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Molecular Biology

2009

Don Oliver

Articles 1 - 6 of 6

Full-Text Articles in Biochemistry, Biophysics, and Structural Biology

Nucleotide And Phospholipid-Dependent Control Of Ppxd And C-Domain Association For Seca Atpase, Don Oliver Dec 2009

Nucleotide And Phospholipid-Dependent Control Of Ppxd And C-Domain Association For Seca Atpase, Don Oliver

Don Oliver

The SecA ATPase motor is a central component of the eubacterial protein translocation machinery. It is comprised of N- and C-domain substructures, where the N-domain is comprised of two nucleotide-binding domains that flank a preprotein-binding domain (PPXD), while the C-domain binds phospholipids as well as SecB chaperone. Our recent crystal structure of Bacillus subtilis SecA protomer [Hunt, J. F., Weinkauf, S., Henry, L., Fak, J. J., McNicholas, P., Oliver, D. B., and Deisenhofer, J. (2002) Science 297, 2018-2026] along with experimental support for the correct dimer structure [Ding, H., Hunt, J. F., Mukerji, I., and Oliver, D. (2003) Biochemistry 42 ...


Role Of A Conserved Glutamate Residue In The Escherichia Coli Seca Atpase Mechanism, Don Oliver Dec 2009

Role Of A Conserved Glutamate Residue In The Escherichia Coli Seca Atpase Mechanism, Don Oliver

Don Oliver

Escherichia coli SecA uses ATP to drive the transport of proteins across cell membranes. Glutamate 210 in the "DEVD" Walker B motif of the SecA ATP-binding site has been proposed as the catalytic base for ATP hydrolysis (Hunt, J. F., Weinkauf, S., Henry, L., Fak, J. J., McNicholas, P., Oliver, D. B., and Deisenhofer, J. (2002) Science 297, 2018-2026). Consistent with this hypothesis, we find that mutation of glutamate 210 to aspartate results in a 90-fold reduction of the ATP hydrolysis rate compared with wild type SecA, 0.3 s(-1) versus 27 s(-1), respectively. SecA-E210D also releases ADP ...


Dimeric Seca Is Essential For Protein Translocation, Don Oliver Dec 2009

Dimeric Seca Is Essential For Protein Translocation, Don Oliver

Don Oliver

SecA facilitates bacterial protein translocation by its association with presecretory or membrane proteins and the SecYEG translocon channel. Once assembled, SecA ATPase undergoes cycles of membrane insertion and retraction at SecYEG that drive protein translocation in a stepwise fashion. SecA exists in equilibrium between a monomer and dimer, and association with its translocation ligands shifts this equilibrium dramatically. Here, we examined the proposal that protein translocation can occur by means of a SecA monomer. We produced a mutant SecA protein lacking residues 2-11, which was found to exist mostly as a monomer, and it was unable to complement a conditional-lethal ...


Reexamination Of The Role Of The Amino Terminus Of Seca In Promoting Its Dimerization And Functional State, Don Oliver Dec 2009

Reexamination Of The Role Of The Amino Terminus Of Seca In Promoting Its Dimerization And Functional State, Don Oliver

Don Oliver

No abstract provided.


Seca Dimer Cross-Linked At Its Subunit Interface Is Functional For Protein Translocation, Don Oliver Dec 2009

Seca Dimer Cross-Linked At Its Subunit Interface Is Functional For Protein Translocation, Don Oliver

Don Oliver

SecA facilitates protein transport across the eubacterial plasma membrane by its association with cargo proteins and the SecYEG translocon, followed by ATP-driven conformational changes that promote protein translocation in a stepwise manner. Whether SecA functions as a monomer or a dimer during this process has been the subject of considerable controversy. Here we utilize cysteine-directed mutagenesis along with the crystal structure of the SecA dimer to create a cross-linked dimer at its subunit interface, which was normally active for in vitro protein translocation.


In Vivo Membrane Topology Of Escherichia Coli Seca Atpase Reveals Extensive Periplasmic Exposure Of Multiple Functionally Important Domains Clustering On One Face Of Seca, Don Oliver Dec 2009

In Vivo Membrane Topology Of Escherichia Coli Seca Atpase Reveals Extensive Periplasmic Exposure Of Multiple Functionally Important Domains Clustering On One Face Of Seca, Don Oliver

Don Oliver

No abstract provided.