Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.1.26.9 (ribonuclease)
 6,589 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The interactions of tryptophan-59 (TRP-59) and its protein environment in ribonuclease-T1 (RNAse-T1) were examined in a 50-ps molecular dynamics simulation. The simulation used was previously shown to demonstrate a fluorescence anisotropy decay that closely agreed with the experimentally determined limiting anisotropy for RNAse-T1 (Axelsen, P. H., C. Haydock, and F. G. Prendergast. 1988. Biophys. J. 54:249-258). Further characterization of TRP-59 side chain dynamics and its protein environment has now been completed and correlated to other photophysical properties of this protein. Angular fluctuations of the side chain occur at rates of 1-10 cycles/ps and are limited to +/- 0.3 radians in all directions. Side chain motions are primarily limited by nonpolar collisions, although most side chain atoms have some collisional contact with polar atoms in the adjacent protein matrix or water. The steric relationship between PRO-39 and TRP-59 changes abruptly at 16 ps into the simulation. Two types of interaction with water are observed. First, a structural water appears to H-bond with the greater than N-H group of TRP-59. Second, water frequently contacts the six-atom ring. The electrostatic field experienced by the TRP-59 rings appears to be relatively constant and featureless regardless of ring orientation. We make the following interferences from our data: The fluorescent emission of TRP-59 may be red-shifted relative to TRP in nonpolar solvents either as a result of specific interactions with the structural water or relaxations of proximal bulk water and polar protein moieties. The quenching efficiency of polar interactions with TRP-59 must be extremely low given their frequency and the high quantum yield of RNAse-T1. This low efficiency may be due to restricted and unfavorable interaction geometries. PRO-39 is located near two titratable HIS residues in RNAse-T1 and may be involved in pH-dependent fluorescence phenomena by virtue of a metastable interaction with TRP-59. The interaction of bulk water with TRP-59 illustrates features of the gated transition state model for transient exposure to exogenously added collisional quenching agents. The restrictive environment of TRP-59 suggests that extrinsic quenching can only occur via interactions with the edge of the indole six-atom ring and that the efficiency of a quencher in a protein environment is likely to be a function of molecular symmetry.
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PMID:Molecular dynamics of tryptophan in ribonuclease-T1. II. Correlations with fluorescence. 250 98

Thermosensitive TRP channels display unique thermal responses, suggesting distinct roles mediating sensory transmission of temperature. However, whether relative expression of these channels in dorsal root ganglia (DRG) is altered in nerve injury is unknown. We developed a multiplex ribonuclease protection assay (RPA) to quantify rat TRPV1, TRPV2, TRPV3, TRPV4, TRPA1, and TRPM8 RNA levels in DRG. We used the multiplex RPA to measure thermosensitive TRP channel RNA levels in DRG from RTX-treated rats (300 microg/kg) or rats with unilateral sciatic nerve chronic constriction injury (CCI). TRPV1 and TRPA1 RNA were significantly decreased in DRG from RTX-treated rats, indicating functional colocalization of TRPA1 and TRPV1 in sensory nociceptors. In DRG from CCI rats, TRPA1, TRPV2, and TRPM8 RNA showed slight but significant increases ipsilateral to peripheral nerve injury. Our findings support the hypothesis that increased TRP channel expression in sensory neurons may contribute to mechanical and cold hypersensitivity.
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PMID:Increased TRPA1, TRPM8, and TRPV2 expression in dorsal root ganglia by nerve injury. 1751 74