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E S Carter

Publications and source records attributed to E S Carter.

5 recordsLinked to original sources
PubMed2001

Sudden productivity collapse associated with the Triassic-Jurassic boundary mass extinction.

The end-Triassic mass extinction is one of the five most catastrophic in Phanerozoic Earth history. Here we report carbon isotope evidence of a pronounced productivity collapse at the boundary, coincident with a sudden extinction among marine plankton, from stratigraphic sections on the Queen Charlotte Islands, British Columbia, Canada. This signal is similar to (though smaller than) the carbon isotope excursions associated with the Permian-Triassic and Cretaceous-Tertiary events.

Animals↗
PubMed1996

NAMOT2--a redesigned nucleic acid modeling tool: construction of non-canonical DNA structures.

Using a new set of reduced coordinates developed for describing regular and unusual nucleic acid structures, we have revised our nucleic acid modeling tool NAMOT2. NAMOT2 is general in terms of modeling different nucleic acid structures. A set of modifiable libraries allows users to customize their modeling environment. With this set of libraries, NAMOT2 can be used to model non-canonical structures such as parallel-stranded, triple-stranded and quadruple-stranded nucleic acid molecules. For modeling irregular structures (junctions, hairpin loops, etc.), we introduce a structural recipe approach. The complete procedure using NAMOT2 to construct the structure of a specific molecule is treated as the recipe for that structural motif. The existing recipes can be modified to generate new recipes for different structural motifs. Several examples of nucleic acids with non-canonical structures were modeled using NAMOT2. These examples include a DNA-drug complex, a DNA cube, a six-arm junction and a curved DNA molecule.

Base Sequence↗
PubMed1994

Nucleic acid modeling tool (NAMOT): an interactive graphic tool for modeling nucleic acid structures.

The helical nature of the molecule (almost all of the DNA and a significant portion of the RNA) makes the modeling of nucleic acids a unique task. Unlike other biopolymers (proteins, lipids, etc.), the integrity the structure of a nucleic acid molecule depends strongly on the maintenance of the base pairing within the molecule. Structural alterations (bending, stretching, compressing, etc.), in general, should not disturb the base pairings. A custom-made molecular modeling tool is developed taking into consideration this specific property of the molecule. Instead of Cartesian coordinates, the modeling is carried out on a set of reduced coordinates developed here in our laboratory. One of the advantages using this set of reduced coordinates is the readiness of maintaining the base pairings while altering the structure. A graphic routine is incorporated into the package to display the image of the molecule while the modeling work is being executed. The program is written in C using XView tool kit with Xlib routines to ensure portability to different workstations.

Algorithms↗
PubMed1992

Conformational analysis of Met-enkephalin in both aqueous solution and in the presence of sodium dodecyl sulfate micelles using multidimensional NMR and molecular modeling.

Proton and 13C chemical shift assignments are reported for the neuropeptide Met-enkephalin (ME) in both aqueous solution and in the presence of 50 mM sodium dodecyl sulfate (SDS). Rotating frame nuclear Overhauser enhancement spectroscopy was used to qualitatively describe interproton distances. These distances were then used as restraints in the distance geometry based molecular modeling program Dspace, developed by Hare Research to generate sets of conformations of ME. The resulting aqueous solution conformations of ME were determined to exhibit characteristic of an extended random-coil polypeptide with no distinguishable secondary structure. The resulting set of solution conformations of ME in the presence of 50 mM SDS exhibited characteristics of an amphiphilic type IV beta turn that are stabilized by hydrophobic aromatic-aromatic interactions between the side chains of Tyr1 and Phe4.

Amino Acid Sequence↗