Showing papers by "Brian R. Crane published in 2005"
TL;DR: Measurements of photochemically induced ET and subsequent charge recombination between Zn-porphyrin-substituted cy tochrome c peroxidase and cytochrome c in single crystals correlate reactivity with defined structures for different association modes of the redox partners.
Abstract: Although bonding networks determine electron-transfer (ET) rates within proteins, the mechanism by which structure and dynamics influence ET across protein interfaces is not well understood. Measurements of photochemically induced ET and subsequent charge recombination between Zn-porphyrin-substituted cytochrome c peroxidase and cytochrome c in single crystals correlate reactivity with defined structures for different association modes of the redox partners. Structures and ET rates in crystals are consistent with tryptophan oxidation mediating charge recombination reactions. Conservative mutations at the interface can drastically affect how the proteins orient and dispose redox centers. Whereas some configurations are ET inactive, the wild-type complex exhibits the fastest recombination rate. Other association modes generate ET rates that do not correlate with predictions based on cofactor separations or simple bonding pathways. Inhibition of photoinduced ET at <273 K indicates gating by small-amplitude dynamics, even within the crystal. Thus, different associations achieve states of similar reactivity, and within those states conformational fluctuations enable interprotein ET.
42 citations
TL;DR: The loose dimer structure indicates that non-native interactions can mediate subunit association in NOS and converts loose dimers to tight dimers in solution and crystals.
42 citations
TL;DR: High resolution crystallographic studies revealed that although all mutants disrupt the hydrogen-bonding network to varying degrees, none affect the conformation of His-45, and 15N-NMR chemical shift studies showed that Glu-67 functions to stabilize the unfavored Nδ1H tautomer of His, thereby rendering the Nϵ2 imidazole unprotonated and well positioned for accepting the ATP phosphoryl group.
39 citations
TL;DR: The crystal structures of TrpRS II bound to tryptophan and 5-HRP reveal residue substitutions that accommodate modified indoles that conserve this capacity to charge tRNA with nonstandard amino acids.
Abstract: The most divergent of two tryptophanyl tRNA synthetases (TrpRS II) found in Deinococcus radiodurans interacts with a nitric oxide synthase protein that produces 4-nitro-tryptophan (4-NRP). TrpRS II efficiently charges transfer RNATrp with 4-NRP and 5-hydroxy-tryptophan (5-HRP). The crystal structures of TrpRS II bound to tryptophan and 5-HRP reveal residue substitutions that accommodate modified indoles. A class of auxiliary bacterial TrpRSs conserve this capacity to charge tRNA with nonstandard amino acids.
32 citations
TL;DR: The structure of drTrpRS II provides a framework for the design of potentially useful antibiotics and is confirmed by thermodynamic measurements and explained by an asymmetric shift of the dimer interface toward the occupied active site.
22 citations