Transactions and proceedings of the New Zealand Institute.

v.20 (1887)

DNA-strand exchange promoted by RecA protein in the absence of ATP: implications for the mechanism of energy transduction in protein-promoted nucleic acid transactions.

DNA-strand exchange promoted by Escherichia coli RecA protein normally requires the presence of ATP and is accompanied by ATP hydrolysis, thereby implying a need for ATP hydrolysis. Previously, ATP hydrolysis was shown not to be required; here we demonstrate furthermore that a nucleoside triphosphate cofactor is not required for DNA-strand exchange. A gratuitous allosteric effector consisting of the noncovalent complex of ADP and aluminum fluoride, ADP.AIF4-, can both induce the high-affinity DNA-binding state of RecA protein and support the homologous pairing and exchange of up to 800-900 bp of DNA. These results demonstrate that induction of the functionally active, high-affinity DNA-binding state of RecA protein is needed for RecA protein-promoted DNA-strand exchange and that there is no requirement for a high-energy nucleotide cofactor for the exchange of DNA strands. Consequently, the free energy needed to activate the DNA substrates for DNA-strand exchange is not derived from ATP hydrolysis. Instead, the needed free energy is derived from ligand binding and is transduced to the DNA via the associated ligand-induced structural transitions of the RecA protein-DNA complex; ATP hydrolysis simply destroys the effector ligand. This concept has general applicability to the mechanism of energy transduction by proteins.

Explaining transactions in time banks in economic crisis

This article studies the services exchanged in a particular Spanish time bank. Using data from users and transactions, we analyse the users’ profile as well as the determinants of providing and receiving different services. Our results show that the representative user is a Spanish female, not married, middle aged, highly educated and unemployed. We also find differences in the personal characteristics driving the supply and demand of services.

Transactions of the Illinois State Horticultural Society for ...

n.s. v. 13

Transactions of the Illinois State Horticultural Society for ...

n.s. v. 23

Transactions of the Wisconsin Academy of Sciences, Arts, and Letters.

13

Transactions of the Sapporo Natural History Society.

5-7

Transactions of the Illinois State Horticultural Society for ...

n.s. v. 9

Transactions of the State Agricultural Society ...

7, 1855

Notes on the Transactions of the Royal Society of London, undated

This folder contains four documents with undated notes about the College's holdings of the Philosophical Transactions of the Royal Society of London.

Transactions of the San Diego Society of Natural History.

v.17 (1972-1975)

Transactions of the San Diego Society of Natural History.

v.10 (1943-1946)

Transactions of the San Diego Society of Natural History.

v.4 (1925)

Transactions of the San Diego Society of Natural History.

v.14 (1965-1967)