脊椎動物の視覚を担うロドプシンは光で活性状態を生成する．しかし，この状態から光でも熱でも直接元の不活性状態に戻ることができない．本稿では，ロドプシンが「光活性化」に特化したメカニズムに迫るため，活性状態から光でも熱でも元の不活性状態に戻る変異体を1アミノ酸置換で作製したので紹介する．

A systematic study of the effect of substitution within the beta-amino acid framework indicates that both beta(2)- and beta(3)-amino acids catalyse the Hajos-Parrish-Eder-Sauer-Wiechert reaction with poor to reasonable levels of enantioselectivity. These results led to the evaluation of the conformationally constrained beta-amino acid (1R,2S)-cispentacin, which catalyses the Hajos-Parrish-Eder-...

The effect of osmotic pressure of diets on be food intake of young rats was investigated by comparing the nutritional effect of casein with the corresponding amino acid mixture at 3.2% nitrogen level. Changes in the osmolarity of diets due to the type of dietary carbohydrate had a little effect on food intake, whereas partial substitution of casein for amino acids resulted in significant increa...

AAindex is a database of numerical indices representing various physicochemical and biochemical properties of amino acids and pairs of amino acids. We have added a collection of protein contact potentials to the AAindex as a new section. Accordingly AAindex consists of three sections now: AAindex1 for the amino acid index of 20 numerical values, AAindex2 for the amino acid substitution matrix a...

Codon-and amino acid-substitution models are widely used for the evolutionary analysis of protein-coding DNA sequences. Using codon models, the amounts of both nonsynonymous and synonymous DNA substitutions can be estimated. The ratio of these amounts represents the strength of selective pressure. Using amino acid models, the amount of nonsynonymous substitutions is estimated, but that of synon...

Aminoacidopathies are a group of rare and diverse disorders, caused by the deficiency of an enzyme or transporter involved in amino acid metabolism. For most aminoacidopathies, dietary management is the mainstay of treatment. Such treatment includes severe natural protein restriction, combined with protein substitution with all amino acids except the amino acids prior to the metabolic block and...

The evolution of model proteins under selection for thermodynamic stability suggests parallels between evolutionary behavior and chemical reaction kinetics. We developed a statistical mechanics theory of protein evolution by dividing amino acid interactions into site-specific and ‘bath’ components, and show that substitutions between two amino acids occur when their site-specific contributions ...

The mechanism of unidirectional transport of glutamine from blood to brain in pentobarbital-anesthetized rats was examined using in situ perfusion. Amino acid uptake into brain across the blood-brain barrier (BBB) is classically thought to be via the Na-independent large neutral (L-system), acidic and basic amino acid transporters. In the presence of physiological concentrations of amino acids ...

A number of transcriptional regulators mediate their effects through direct contact with the 70 subunit of Escherichia coli RNA polymerase (RNAP). In particular, several regulators have been shown to contact a C-terminal portion of 70 that harbors conserved region 4. This region of contains a putative helix-turn-helix DNA-binding motif that contacts the 35 element of -dependent promoters direct...

We have isolated a cDNA clone encoding pancreatic polypeptide from a cDNA library constructed with RNA from an endocrine neoplasm of the human pancreas. The cDNA was inserted into plasmid pBR322 and the plasmid was cloned in Escherichia coli. Oligonucleotides (sequence in text) specific for the amino acid sequence (sequence in text) of pancreatic polypeptide were used as hybridization probes. T...