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C E Schutt

Publications and source records attributed to C E Schutt.

47 records · Page 3Linked to original sources
PubMed1989

Molecular packing in profilin: actin crystals and its implications.

Analysis of profilin: actin crystals reveals an extensive intermolecular network, rather than a discrete "monomeric complex", comprising stacked actin ribbons held in place by columns of profilin molecules, wedged in between neighboring actin subunits and running perpendicular to the ribbons. Comparison with data from electron microscopy, X-ray diffraction, spectroscopy, and biochemistry of actin suggests that a simple transformation relates the ribbon to f-actin. The crystals exhibit unusual polymorphic properties, which strengthens the view that movements within the actin monomer are important for force generation.

Actins↗
PubMed1989

Three-dimensional structure of CheY, the response regulator of bacterial chemotaxis.

Homologies among bacterial signal transduction proteins suggest that a common mechanism mediates processes such as chemotaxis, osmoregulation, sporulation, virulence, and responses to nitrogen, phosphorous and oxygen deprivation. A common kinase-mediated phosphotransfer reaction has recently been identified in chemotaxis, nitrogen regulation, and osmoregulation. In chemotaxis, the CheA kinase passes a phosphoryl group to the cytoplasmic protein CheY, which functions as a phosphorylation-activated switch that interacts with flagellar components to regulate motility. We report here the X-ray crystal structure of the Salmonella typhimurium CheY protein. The determination of the structure was facilitated by the use of site-specific mutagenesis to engineer heavy-atom binding sites. CheY is a single-domain protein composed of a doubly wound five-stranded parallel beta-sheet. The phosphoacceptor site in CheY is probably a cluster of aspartic-acid side chains near the C-terminal edge of the beta-sheet. The pattern of sequence similarity of CheY with components of other regulatory systems can be interpreted in the light of the CheY structure and supports the view that this family of proteins have a common structural motif and active site.

Bacterial Proteins↗
PubMed1989

Molecular dynamics simulation of a phospholipid micelle.

The dynamic character of phospholipid aggregates limits conventional structural studies to the determination of average molecular features. In order to develop more detailed descriptions of phospholipid structure for comparison with experiment, the molecular dynamics of a hydrated lysophosphatidylethanolamine (LPE) micelle, incorporating 85 LPE and 1591 water molecules, have been simulated. Comparison of the initial and equilibrated micelles shows substantial differences both in LPE hydrocarbon chain conformation and polar head-group-solvent interactions. Although these changes produce only subtle effects on the averaged structural properties of the system, the alterations in hydrocarbon chain packing and head-group solvation appear to mimic a polymorphic pretransition from a spherical toward a cylindrical micelle structure.

Colloids↗
PubMed1989

Analytical determination of methylated histidine in proteins: actin methylation.

The methylation of histidine in actin from various muscle and nonmuscle sources has been studied by formation of phenylthiocarbamyl derivatives and subsequent reverse-phase high-pressure liquid chromatographic separation and analysis of actin hydrolyzates. All the actin species examined were found to contain 3-methylhistidine. This method has also been used in assays for the enzyme(s) responsible for methylation of rabbit skeletal muscle actin and to investigate the formation of other methylated residues in vitro. 3-Methyl-histidine is the major methylation product in this in vitro reaction.

Actins↗
PubMed1988

The use of poly(L-proline)-Sepharose in the isolation of profilin and profilactin complexes.

In the purification of proline hydroxylase by affinity chromatography on poly(L-proline)-Sepharose it was found earlier that two other components, profilin and the complex profilin-actin, also bind with high affinity to this matrix. We have exploited this observation to develop a rapid procedure for the isolation of profilin and profilin-actin complexes in high yields directly from high-speed supernatants of crude tissue-extracts. Through an extensive search for elution conditions, avoiding poly(L-proline) as the desorbant, we have found that active proteins can be recovered from the affinity column with a buffer containing 30% dimethyl sulphoxide. Subsequent chromatography on hydroxylapatite separates free profilin and the two isoforms of profilactin, profilin-actin beta and profilin-actin gamma. The profilin-actin complexes produced this way have high specific activities in the DNAase-inhibition assay, give rise to filaments on addition of Mg2+, and can be crystallized. From the isolated profilin-actin complexes the beta- and gamma-actin isoforms of non-muscle cells can easily be prepared in a polymerization competent form. Pure profilin is either obtained from an excess pool present in some extracts or by dissociation of profilin-actin complexes and removal of the actin.

Actins↗
PubMed1977

Tomato bushy stunt virus at 5.5-A resolution.

The coat of tomato bushy stunt virus is built from protein subunits having rigid domains connected by a flexible hinge. Two states of the hinge are present in the T=3 icosahedral structure. Each subunit has a binding site for RNA on its inner surface.

Nucleic Acid Conformation↗