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C P Holmes

Publications and source records attributed to C P Holmes.

6 recordsLinked to original sources
PubMed1999

A peroxisome proliferator-activated receptor gamma ligand inhibits adipocyte differentiation.

The peroxisome proliferator-activated receptors (PPARs) are nuclear hormone receptors that regulate glucose and lipid homeostasis. The PPARgamma subtype plays a central role in the regulation of adipogenesis and is the molecular target for the 2, 4-thiazolidinedione class of antidiabetic drugs. Structural studies have revealed that agonist ligands activate the PPARs through direct interactions with the C-terminal region of the ligand-binding domain, which includes the activation function 2 helix. GW0072 was identified as a high-affinity PPARgamma ligand that was a weak partial agonist of PPARgamma transactivation. X-ray crystallography revealed that GW0072 occupied the ligand-binding pocket by using different epitopes than the known PPAR agonists and did not interact with the activation function 2 helix. In cell culture, GW0072 was a potent antagonist of adipocyte differentiation. These results establish an approach to the design of PPAR ligands with modified biological activities.

Adipocytes↗
PubMed1996

Versatile approach to encoding combinatorial organic syntheses using chemically robust secondary amine tags.

Encoded combinatorial organic synthesis has recently emerged as a powerful tool for the discovery of biologically active compounds from complex chemical libraries. This report describes a new encoding methodology that uses chemically robust secondary amines as tags. These amines are incorporated into an N-[(dialkylcarbamoyl)methyl]glycine-coding oligomer through simple chemistry that is compatible with a wide range of polymer-supported transformations useful in combinatorial synthesis. In the decoding process acidic hydrolysis of the tagging polymer regenerates the secondary amines, which after dansylation are resolved and detected at sub-picomole levels by reversed-phase HPLC. The versatility of this strategy is demonstrated here by encoded syntheses of members of several representative heterocyclic compound classes, including beta-lactams, 4-thiazolidinones, and pyrrolidines.

Anti-Bacterial Agents↗
PubMed1995

The use of light-directed combinatorial peptide synthesis in epitope mapping.

The application of light-directed combinatorial peptide synthesis to epitope mapping is described. Photolithography and solid phase peptide synthesis were combined in an automated fashion to assemble arrays containing 1024 peptide sequences on a glass support in ten steps with the precise location of each peptide known. The simultaneous synthesis of two slides containing three arrays of peptides each allowed for the independent screening of both a monoclonal antibody (mAb) and its Fab fragment at two different concentrations. A binary synthesis strategy was used to assemble the arrays, resulting in all deletions and truncations possible within the FLRRQFKVVT sequence being present and available for screening. The relative binding interactions of each peptide was determined by incubating the arrays with either mAb D32.39 and goat antimouse immunoglobulin G-FITC or mAb D32.39 Fab-FITC conjugate, followed by scanning the surface for fluorescence with an epifluorescence microscope. The fragment RQFKVVT was found to bind tightly to both the mAb and Fab fragment while tethered to the surface, and was measured to have 0.49 nM affinity in solution. The frame-shifted RRQFKVV sequence was found to have lower affinity both in solution (1.3 mM) and on the surface. The fragment RQFKVV was determined to be responsible for antibody recognition and was found to bind tightly when tethered to the surface, yet exhibited no binding in solution as the free acid, suggesting the requirement of an amidated C-terminus or an additional flanking residue. A deletion analysis revealed that the novel RQFKVT sequence exhibited higher affinity than the RQFKVV sequence while tethered to the surface.

Amino Acid Sequence↗
PubMed1994

Light-generated oligonucleotide arrays for rapid DNA sequence analysis.

In many areas of molecular biology there is a need to rapidly extract and analyze genetic information; however, current technologies for DNA sequence analysis are slow and labor intensive. We report here how modern photolithographic techniques can be used to facilitate sequence analysis by generating miniaturized arrays of densely packed oligonucleotide probes. These probe arrays, or DNA chips, can then be applied to parallel DNA hybridization analysis, directly yielding sequence information. In a preliminary experiment, a 1.28 x 1.28 cm array of 256 different octanucleotides was produced in 16 chemical reaction cycles, requiring 4 hr to complete. The hybridization pattern of fluorescently labeled oligonucleotide targets was then detected by epifluorescence microscopy. The fluorescence signals from complementary probes were 5-35 times stronger than those with single or double base-pair hybridization mismatches, demonstrating specificity in the identification of complementary sequences. This method should prove to be a powerful tool for rapid investigations in human genetics and diagnostics, pathogen detection, and DNA molecular recognition.

Base Sequence↗