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Social and Behavioral Sciences Commons

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Full-Text Articles in Social and Behavioral Sciences

An Allometric Comparison Of Microsomal Membrane Lipid Composition And Sodium Pump Molecular Activity In The Brain Of Mammals And Birds, Anthony J. Hulbert, Paul Else, Nigel Turner Jan 2005

An Allometric Comparison Of Microsomal Membrane Lipid Composition And Sodium Pump Molecular Activity In The Brain Of Mammals And Birds, Anthony J. Hulbert, Paul Else, Nigel Turner

Faculty of Health and Behavioural Sciences - Papers (Archive)

Previous research has shown that the lipid milieu surrounding membrane proteins may be an important factor in determining their activity. To investigate this we have examined sodium pump molecular activity and microsomal membrane lipid composition in the brain of five mammalian and eight avian species ranging in size from 30 g mice to 280 kg cattle and 13 g zebra finches to 35 kg emus, respectively. Sodium pump (Na+,K+-ATPase) activity was higher in the smaller species and showed a significant allometric decline with body mass in both the mammals (μmol Pi h-1 mg wet …


Enzyme Activity And Flexibility At Very Low Hydration, V Kurkal, R M. Daniel, John L. Finney, Moeava Tehei, R V. Dunn, Jeremy C. Smith Jan 2005

Enzyme Activity And Flexibility At Very Low Hydration, V Kurkal, R M. Daniel, John L. Finney, Moeava Tehei, R V. Dunn, Jeremy C. Smith

Faculty of Science, Medicine and Health - Papers: part A

Recent measurements have demonstrated enzyme activity at hydrations as low as 3%. This raises the question of whether hydration-induced enzyme flexibility is important for activity. Here, to address this, picosecond dynamic neutron scattering experiments are performed on pig liver esterase powders at 0%, 3%, 12%, and 50% hydration by weight and at temperatures ranging from 120 to 300 K. At all temperatures and hydrations, significant quasielastic scattering intensity is found in the protein, indicating the presence of anharmonic, diffusive motion. As the hydration increases, a temperature-dependent dynamical transition appears and strengthens involving additional diffusive motion. The implication of these results …


Replication Termination In Escherichia Coli: Structure And Anti-Helicase Activity Of The Tus-Ter Complex, Cameron Neylon, Andrew V. Kralicek, Thomas M. Hill, Nicholas E. Dixon Jan 2005

Replication Termination In Escherichia Coli: Structure And Anti-Helicase Activity Of The Tus-Ter Complex, Cameron Neylon, Andrew V. Kralicek, Thomas M. Hill, Nicholas E. Dixon

Faculty of Science, Medicine and Health - Papers: part A

The arrest of DNA replication in Escherichia coli is triggered by the encounter of a replisome with a Tus protein-Ter DNA complex. A replication fork can pass through a Tus-Ter complex when traveling in one direction but not the other, and the chromosomal Ter sites are oriented so replication forks can enter, but not exit, the terminus region. The Tus-Ter complex acts by blocking the action of the replicative DnaB helicase, but details of the mechanism are uncertain. One proposed mechanism involves a specific interaction between Tus-Ter and the helicase that prevents further DNA unwinding, while …