Interaction of the human DnaJ homologue, HSJ1b with the 90 kDa heat shock protein, Hsp90

The 90 kDa heat shock protein (Hsp90) is a major cytoplasmic molecular chaperone associating with numerous other proteins. Both genetic and in vitro refolding experiments using reticulocyte lysate have suggested a functional interaction of Hsp90 with yeast human homologues of E. coli DnaJ. Here we present direct evidence using surface plasmon resonance that Hsp90 and the human DnaJ homologue, HSJ1b, bind to each other. We also show that Hsp90 and HSJ1b transfer alpha-lactalbumin to each other in an ATP-dependent manner. The two chaperones have additive effects in preventing rhodanese aggregation.     

A common and recurrent 13-bp deletion in the autoimmune regulator gene in British kindreds with autoimmune polyendocrinopathy type 1.

Autoimmune polyendocrinopathy type 1 (APS1) is an autosomal recessive disorder characterized by autoimmune hypoparathyroidism, autoimmune adrenocortical failure, and mucocutaneous candidiasis. Recently, an autoimmune regulator gene (AIRE-1), which is located on chromosome 21q22.3, has been identified, and mutations in European kindreds with APS1 have been described. We used SSCP analysis and direct DNA sequencing to screen the entire 1,635-bp coding region of AIRE-1 in 12 British families with APS1. A 13-bp deletion (964del13) was found to account for 17 of the 24 possible mutant AIRE-1 alleles, in our kindreds. This mutation was found to occur de novo in one affected subject. A common haplotype spanning the AIRE-1 locus was found in chromosomes that carried the 964del13 mutation, suggesting a founder effect in our population. One of 576 normal subjects was also a heterozygous carrier of the 964del13 mutation. Six other point mutations were found in AIRE-1, including two 1-bp deletions, three missense mutations (R15L, L28P, and Y90C), and a nonsense mutation (R257*). The high frequency of the 964del13 allele and the clustering of the other AIRE-1 mutations may allow rapid molecular screening for APS1 in British kindreds. Furthermore, the prevalence of the 964del13 AIRE-1 mutation may have implications in the pathogenesis of the more common autoimmune endocrinopathies in our population.     

Oxygen-17 NMR relaxation studies on gelatinization temperature and water mobility in maize starches

The effects of starch/water ratio, amylose content, degree of phosphorylation, and added KI on water mobility in maize starch-water dispersions were studied by oxygen-17 spin-spin relaxation time measurements over a range of temperatures. The results demonstrate that: (i) the changes in spin-spin relaxation time (ΔT₂) reflect the degree of starch-water interaction at different stages of the heating process; (ii) the amount of added water affects the initial T₂ and ΔT₂ during gelatinization; (iii) higher amylose contents result in lower water mobility in starch-water systems; (iv) higher degrees of phosphorylation lead to a decrease in water mobility, accompanied by a decrease in gelatinization temperature; and (v) added KI effectively decreases water mobility and gelatinization temperature in the starch-water systems studied.     

Structure, function and evolution of DnaJ: conservation and adaptation of chaperone function

No Abstract Available     

Transcriptional profiling of bovine intervertebral disc cells: implications for identification of normal and degenerate human intervertebral disc cell phenotypes

Introduction  

Nucleus pulposus (NP) cells have a phenotype similar to articular cartilage (AC) cells. However, the matrix of the NP is clearly different to that of AC suggesting that specific cell phenotypes exist. The aim of this study was to identify novel genes that could be used to distinguish bovine NP cells from AC and annulus fibrosus (AF) cells, and to further determine their expression in normal and degenerate human intervertebral disc (IVD) cells.     

Biocatalytic synthesis of disaccharide high-intensity sweeterner sucralose via a tetrachlororaffinose intermediate

A second high-yielding bioorganic synthesis of the highintensity sweetener sucralose (4,1',6'-trichloro-4,1',6'-trideoxygalactosucrose) is described. This procedure involves the chemical chlorination of raffinose to form a novel tetrachloroaffinose intermediate (6,4',1',6'-tetrachloro-6,4',1',6'-tetradeoxygalactoraffinose; TCR) followed by the enzymic hydrolysis of the alpha-1-6 glycosidic bond of TCR to give sucralose and 6-chlorogalactose. Commercial enzyme preparations and microorganisms were screened to select alpha-galactosidases which have high catalytic activity on this compound. The most active enzyme was produced by a strain of Mortierella vinacea and had a maximum rate of 118 mumol sucralose/g dry weight cells/h, which was approximately 5% of the activity toward raffinose, and a K(m) of 5.8 mM toward TCR. The enzyme could be used in the form of mycelial pellets in a continuous packed bed column reactor. The reaction was also studied in a water-immiscible hydrophilic organic solvent, such as methyl isobutyl ketone, to overcome the poor aqueous solubility of TCR and to increase volumetric productivity. Synthesis of raffinose was achieved from saturated aqueous solutions of galactose and sucrose using a selected alpha-galactosidase from Aspergillus niger. When raffinose is used as a starting material for sucralose synthesis, this route has fewer steps than either the preceeding method using glucose-6-acetate as an intermediate or the complete chemical synthesis from sucrose. The relative merits of the two bioorganic routes and the utility of such methods to synthesize new sugars are discussed.     

Some applications of reversed-phase high-performance liquid chromatography to oligosaccharide separations

Oligosaccharide separation on reversed-phase high-performance liquid chormatographic columns have been examined using a range of aqueous solvents. Addition of anionic, cationic and non-ionic surfactants, tetramethyl urea and organic solvents to the mobile phase cause faster elution of oligosaccharides, and allow the separation of the larger oligomers in an acceptable time. Addition of neutral, inorganic salts increase the retention factors considerably, and allows good resolution of some compounds poorly resolved in water alone.The mechanism operating in the separations approximates to that invoked in the solvophobic theory of reversed-phase chromatography. There is some evidence also of hydrogen bond effects. The improvements described should prove useful in the isolation and analysis of neutral oligosaccharides in general, and in structural analyses of polysaccharides in paritcular.     

The genetic basis of individual-recognition signals in the mouse

The major histocompatibility complex (MHC) is widely assumed to be a primary determinant of individual-recognition scents in many vertebrates [1-6], but there has been no functional test of this in animals with normal levels of genetic variation. Mice have evolved another polygenic and highly polymorphic set of proteins for scent communication, the major urinary proteins (MUPs) [7-12], which may provide a more reliable identity signature ([13, 14] and A.L. Sherborne, M.D.T., S. Paterson, F.J., W.E.R.O., P. Stockley, R.J.B., and J.L.H., unpublished data). We used female preference for males that countermark competitor male scents [15-17] to test the ability of wild-derived mice to recognize individual males differing in MHC or MUP type on a variable genetic background. Differences in MHC type were not used for individual recognition. Instead, recognition depended on a difference in MUP type, regardless of other genetic differences between individuals. Recognition also required scent contact, consistent with detection of involatile components through the vomeronasal system [6, 18]. Other differences in individual scent stimulated investigation but did not result in individual recognition. Contrary to untested assumptions of a vertebrate-wide mechanism based largely on MHC variation, mice use a species-specific [12] individual identity signature that can be recognized reliably despite the complex internal and external factors that influence scents [2]. Specific signals for genetic identity recognition in other species now need to be investigated.