182 research outputs found
Drug transport mechanism of P-glycoprotein monitored by single molecule fluorescence resonance energy transfer
In this work we monitor the catalytic mechanism of P-glycoprotein (Pgp) using
single-molecule fluorescence resonance energy transfer (FRET). Pgp, a member of
the ATP binding cassette family of transport proteins, is found in the plasma
membrane of animal cells where it is involved in the ATP hydrolysis driven
export of hydrophobic molecules. When expressed in the plasma membrane of
cancer cells, the transport activity of Pgp can lead to the failure of
chemotherapy by excluding the mostly hydrophobic drugs from the interior of the
cell. Despite ongoing effort, the catalytic mechanism by which Pgp couples
MgATP binding and hydrolysis to translocation of drug molecules across the
lipid bilayer is poorly understood. Using site directed mutagenesis, we have
introduced cysteine residues for fluorescence labeling into different regions
of the nucleotide binding domains (NBDs) of Pgp. Double-labeled single Pgp
molecules showed fluctuating FRET efficiencies during drug stimulated ATP
hydrolysis suggesting that the NBDs undergo significant movements during
catalysis. Duty cycle-optimized alternating laser excitation (DCO-ALEX) is
applied to minimize FRET artifacts and to select the appropriate molecules. The
data show that Pgp is a highly dynamic enzyme that appears to fluctuate between
at least two major conformations during steady state turnover.Comment: 10 pages, 7 figure
Genetic study of fiber properties in crosses among stormproof and open-boll varieties of cotton using the diallel analysis
Cotton classing in Oklahoma
The Oklahoma Cooperative Extension Service periodically issues revisions to its publications. The most current edition is made available. For access to an earlier edition, if available for this title, please contact the Oklahoma State University Library Archives by email at [email protected] or by phone at 405-744-6311
Avaliação de parâmetros para o preparo de materiais de referência.
Editado por Ana Rita de Araújo; Simone Cristina Méo Nicura
Digestão alcalina de tecido vegetal em forno de micro-ondas para determinação de silicio: uma alternativa aos métodos convencionais.
Adjusting seeding rates to optimize stands of cotton
The Oklahoma Cooperative Extension Service periodically issues revisions to its publications. The most current edition is made available. For access to an earlier edition, if available for this title, please contact the Oklahoma State University Library Archives by email at [email protected] or by phone at 405-744-6311
Choosing which cotton varieties to grow
The Oklahoma Cooperative Extension Service periodically issues revisions to its publications. The most current edition is made available. For access to an earlier edition, if available for this title, please contact the Oklahoma State University Library Archives by email at [email protected] or by phone at 405-744-6311
Adjusting seeding rates to optimize stands of cotton
The Oklahoma Cooperative Extension Service periodically issues revisions to its publications. The most current edition is made available. For access to an earlier edition, if available for this title, please contact the Oklahoma State University Library Archives by email at [email protected] or by phone at 405-744-6311
Choosing which cotton varieties to grow
The Oklahoma Cooperative Extension Service periodically issues revisions to its publications. The most current edition is made available. For access to an earlier edition, if available for this title, please contact the Oklahoma State University Library Archives by email at [email protected] or by phone at 405-744-6311
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