Biomedical subjects

J A Wendel

Publications and source records attributed to J A Wendel.

2 recordsLinked to original sources

PubMed1997

Nucleoprotein-based nanoscale assembly.

A system for addressing in the construction of macromolecular assemblies can be based on the biospecificity of DNA (cytosine-5) methyltransferases and the capacity of these enzymes to form abortive covalent complexes at targeted 5-fluorocytosine residues in DNA. Using this system, macromolecular assemblies have been created using two representative methyltransferases: M-HhaI and M x MspI. When 5-fluorocytosine (F) is placed at the targeted cytosine in each recognition sequence in a synthetic oligodeoxynucleotide (GFGC for M x HhaI or FCGG for M x MspI), we show that the first recognition sequence becomes an address for M x HhaI, while the second sequence becomes an address for M x MspI. A chimeric enzyme containing a dodecapeptide antigen linked to the C terminus of M-HhaI retained its recognition specificity. That specificity served to address the linked peptide to the GFGC recognition site in DNA. With this assembly system components can be placed in a preselected order on the DNA helix. Axial spacing for adjacent addresses can be guided by the observed kinetic footprint of each methyltransferase. Axial rotation of the addressable protein can be guided by the screw axis of the DNA helix. The system has significant potential in the general construction of macromolecular assemblies. We anticipate that these assemblies will be useful in the construction of regular protein arrays for structural analysis, in the construction of protein-DNA systems as models of chromatin and the synaptonemal complex, and in the construction of macromolecular devices.

Base Sequence↗

PubMed1996

Effects of diet composition and ketosis on glycemia during very-low-energy-diet therapy in obese patients with non-insulin-dependent diabetes mellitus.

To determine whether high-ketogenic very-low-energy diets (VLEDs) can reduce hepatic glucose output (HGO) and hyperglycemia more effectively than can low-ketogenic VLEDs in obese patients with non-insulin-dependent diabetes mellitus (NIDDM), seven patients were treated with a high-ketogenic VLED for 3 wk and were compared with six patients treated with a low-ketogenic VLED. All patients were then crossed over and treated with the alternate diet for another 3 wk. Basal HGO, fasting ketone bodies, and glycemia, insulin, and C-peptide after fasting and an oral-glucose-tolerance test (OGTT) were measured. Before treatment, prediet weight and fasting, OGTT, and HGO measurements were not different between groups. After dieting, weight loss was not different between the groups. However, fasting and OGTT glycemia were lower during treatment with the high-ketogenic VLED than with the low-ketogenic VLED (treatment effect: P < 0.05, by analysis of variance). Moreover, there was a strong correlation between basal HGO and fasting plasma ketone bodies (r = -0.71 at 3 wk, r = -0.67 at 6 wk; both P < 0.05). In contrast, fasting and OGTT plasma insulin and C-peptide concentrations were not different between treatment groups. These data indicate that in obese patients with NIDDM, high-ketogenic VLEDs have a more clinically favorable effect on glycemia than do low-ketogenic VLEDs.

Blood Glucose↗