Dominic Lambert

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Osmolytes are small organic molecules accumulated by cells in response to osmotic stress. Although their effects on protein stability have been studied, there has been no systematic documentation of their influence on RNA. Here, the effects of nine osmolytes on the secondary and tertiary structure stabilities of six RNA structures of differing complexity(More)
As a substrate for human liver microsomes, ethoxyresorufin appears to be metabolised by a group of cytochrome P450 isoenzymes which are inducible by cigarette smoking. Kinetic studies in microsomes from four human livers indicate that only one enzyme component is involved over the full substrate range. Ethoxyresorufin O-deethylation activity at both high(More)
The catalytic determinants for the cleavage and ligation reactions mediated by the hairpin ribozyme are integral to the polyribonucleotide chain. We describe experiments that place G8, a critical guanosine, at the active site, and point to an essential role in catalysis. Cross-linking and modeling show that formation of a catalytic complex is accompanied by(More)
To investigate the mechanism by which urea destabilizes RNA structure, urea-induced unfolding of four different RNA secondary and tertiary structures was quantified in terms of an m-value, the rate at which the free energy of unfolding changes with urea molality. From literature data and our osmometric study of a backbone analogue, we derived average(More)
IPRI-MD-66 (MD-66) cells respond to 20-hydroxyecdysone (20E, 4 x 10(-6) M) in the medium by producing cytoplasmic extensions, clumping and attaching themselves to the substrate. These morphological changes are at a maximum by 6 days post treatment. Degenerate oligonucleotides, designed on the basis of conserved amino acid sequences in the DNA and ligand(More)
The two domains of the hairpin ribozyme-substrate complex, usually depicted as straight structural elements, must interact with one another in order to form an active conformation. Little is known about the internal geometry of the individual domains in an active docked complex. Using various crosslinking and structural approaches in conjunction with(More)
We have investigated the isozymes of a phosphoinositide-specific phospholipase C (PLC) in bovine retina using several monoclonal antisera to PLCbeta1, gamma1, and delta1. Immunoblot analysis showed that all three isozymes were present in the retina. Immunocytochemical localization in frozen bovine retina sections showed that PLCgamma1 was present in the(More)
The plasma, in addition to the liver, is a major site of hydrolysis of aspirin. Human plasma and liver aspirin esterase activities in samples from a group of patients varied over a two fold range and there was a significant correlation between individual plasma and liver activities. Human liver aspirin esterase was present in the cytosolic and microsomal(More)
Many RNA tertiary structures are stable in the presence of monovalent ions alone. To evaluate the degree to which ions at or near the surfaces of such RNAs contribute to stability, the salt-dependent stability of a variety of RNA structures was measured with each of the five group I cations. The stability of hairpin secondary structures and a pseudoknot(More)
The hammerhead ribozyme has been intensively studied for approximately 15 years, but its cleavage mechanism is not yet understood. Crystal structures reveal a Y-shaped molecule in which the cleavage site is not ideally aligned for an S(N)2 reaction and no RNA functional groups are positioned appropriately to perform the roles of acid and base or other(More)