Structure of equine corticotropin releasing factor

A 41 amino acid peptide, probably identical in structure to human corticotropin releasing factor, was isolated from 70 equine hypothalami by methanol extraction, immunoaffinity chromatography and single step of reverse phase HPLC. The amino acid sequence was determined by gas phase sequence analysis. Probable carboxyl terminal amidation was demonstrated by similar retention times for equine and human corticotropin releasing factor on reverse phase HPLC at pH 8. The likely structure of equine corticotropin releasing factor is: Ser-Glu-Glu-Pro-Pro- Ile-Ser-Leu-Asp-Leu-Thr-Phe-His-Leu-Leu-Arg-Glu-Val-Leu-Glu-Met-Ala-Arg-Ala-Glu-Gln-Leu-Ala-Gln-Gln-Ala-His-Ser-Asn- Arg-Lys-Leu-Met-Glu-Ile-Ile-NH₂. The purified peptide is equipotent with human corticotropin releasing factor in an in vitro bioassay and in a human plasma binding protein assay.     

Calretinin and calbindin in the retina of the developing chick

Summary Calretinin and calbindin-D28k are two calcium-binding proteins that are present in largely different sets of nerve cells in the central nervous system. Their appearance during development of the chick retina was studied by immunohistochemistry and Western blots. The patterns are mature one day before hatching. Each cell type acquires its characteristic calcium-binding protein several days after its differentiation has started, but in most cases before morphological maturation is complete. There is also an early phase of calbindin immunoreactivity in many immature amacrine cells, and of calretinin immunoreactivity in the presumptive photoreceptor layer, suggesting that these proteins may have distinct functions in differentiating cells.Abbreviations CR+ Immunoreactive for calretinin only - CB+ immunoreactive for calbindin only - CR+CB+ immunoreactive for both antisera - IPL inner plexiform layer - OPL outer plexiform layer     

Purification and characterization of prephenate aminotransferase from Anchusa officinalis cell cultures

Prephenate aminotransferase (PAT) from rosmarinic acid-producing cell cultures of Anchusa officinalis has been purified to apparent electrophoretic homogeneity using a combination of high-performance anion-exchange, chromatofocusing, and gel filtration chromatography. The purified enzyme has a native molecular weight of 220,000 and subunit molecular weights of 44,000 and 57,000, indicating a possible alpha 2 beta 2 subunit structure. The purified PAT displays high affinity for prephenate (Km = 80 microM) but could also utilize other aromatic alpha-keto acids at less than 20% the rate with prephenate. L-Aspartate (Km = 80 microM) is about three times as effective as L-glutamate as amino-donor substrate. Anchusa PAT is not subject to feedback inhibition from L-phenylalanine or tyrosine, but its activity is affected by a rosmarinic acid metabolite, 3,4-dihydroxyphenyllactic acid.     

Temperature dependence of the reduction potential of CuA in carbon monoxide inhibited cytochrome c oxidase

The temperature dependence of the reduction potential of the CuA site in carbon monoxide inhibited cytochrome c oxidase has been measured with a spectroelectrochemical method adapted to the relatively weak near-infrared absorption of this copper ion. These measurements, together with parallel measurements on the 604-nm absorption due to Fea, indicate that an interaction between CuA and Fea causes the reduction potential for one of these sites to be decreased by approximately 40 mV upon reduction of the other. The temperature dependence of the CuA reduction potential indicates a relatively large and negative standard entropy of reduction of CuA (delta So' = -48.7 +/- 2.3 eu). Possible implications of the intersite redox interaction and the large standard entropy of reduction of the CuA site are discussed.     

New common nomenclature for glycoprotein genes of varicella-zoster virus and their glycosylated products.

The accumulation of recent data concerning the reactivity of monoclonal antibodies with particular varicella-zoster virus (VZV) glycoproteins and the mapping of several of their respective genes on the VZV genome has led to a unified nomenclature for the glycoprotein genes of VZV and their mature glycosylated products. Homologs to herpes simplex virus glycoprotein genes are noted.     

Vicilin genes ofPisum

Summary We describe four genomic clones of pea 7S storage protein gene, one of which corresponds to convicilin, and the others to vicilin. Hybridization studies exploiting these clones, and previously identified cDNA clones, have enabled us to define six different loci. Three of these loci have been mapped to positions on chromosome 7.     

Purification and properties of ribulosebisphosphate carboxylase large subunit binding protein

The large subunit binding protein, an abundant plastid protein implicated in the assembly of ribulose-1,5-bisphosphate carboxylase-oxygenase (RubisCO), has been highly purified from leaves of Pisum sativum. The 720 kilodaltons purified binding protein is composed of two types of subunits of 60 and 61 kilodaltons. Highly specific polyclonal antibodies have been raised against the binding protein. The antibodies do not cross-react with the large subunit nor do anti-RubisCO antibodies cross-react with the binding protein. A higher molecular weight form of the binding protein is immunoprecipitated from products of P. sativum polysomes translated in a wheat-germ system, indicating that the binding protein is synthesized by cytoplasmic ribosomes. Immunoblotting reveals the presence of binding protein in extracts of tobacco, wheat and barley leaves and castor bean endosperm.

The previously reported dissociation of the binding protein-large subunit complex upon addition of ATP in vitro has been confirmed and the fates of the dissociated subunits further investigated. The dissociated binding protein subunits are not phosphorylated or adenylated in vitro by added ATP.

     

Isolation and characterization of the TRM1 locus, a gene essential for the N2,N2-dimethylguanosine modification of both mitochondrial and cytoplasmic tRNA in Saccharomyces cerevisiae

The trm1 mutation of Saccharomyces cerevisiae is a single nuclear mutation that affects a specific base modification of both cytoplasmic and mitochondrial tRNA. Transfer RNA isolated from trm1 cells lacks the modified base N2,N2-dimethylguanosine, and extracts from these cells do not have detectable N2,N2-dimethylguanosine-specific tRNA methyltransferase activity. As part of our efforts to determine how this mutation affects enzyme activities in two different cellular compartments we have isolated the TRM1 locus by genetic complementation. The TRM1 locus restores the N2,N2-dimethylguanosine modification to both cytoplasmic and mitochondrial tRNA in trm1 cells. An open reading frame in this TRM1 gene is essential for complementation of the trm1 phenotype. Expression of this open reading frame in Escherichia coli converts the organism from one that neither makes N2,N2-dimethylguanosine nor has N2,N2-dimethylguanosine-specific tRNA methyltransferase activity into one that does. This result suggests that the TRM1 locus is the structural gene for the tRNA modification enzyme and that both nuclear/cytoplasmic and mitochondrial forms of the methyltransferase are produced from the same gene.