A chaperonin from a thermophilic bacterium, Thermus thermophilus, that controls refoldings of several thermophilic enzymes.

A chaperonin has been purified from a thermophilic bacterium, Thermus thermophilus. It consists of two kinds of proteins with approximate Mr 58,000 and 10,000 and shows a 7-fold rotational symmetry from the top view and a "football"-like shape from the side view under the electron microscopic view. Its weak ATPase activity is inhibited by sulfite and activated by bicarbonate. ATP causes change of its mobility in nondenaturating polyacrylamide gel electrophoresis. The T. thermophilus chaperonin can promote in vitro refolding of several guanidine HCl-denatured enzymes from thermophilic bacteria. At high temperatures above 60 degrees C, where the native enzymes are stable but their spontaneous refoldings upon dilution of guanidine HCl fail, the chaperonin induces productive refolding in an ATP-dependent manner. No or very poor refolding is induced when the chaperonin is added to the solution aged after dilution. An excess amount of the chaperonin is inhibitory for refolding. At middle temperatures (30-50 degrees C), where spontaneous refoldings of the enzymes occur, the chaperonin arrests refolding in the absence of ATP and refolding is induced when ATP is supplemented. At temperatures below 20 degrees C, where spontaneous refoldings also occur, the chaperonin arrests the refolding but ATP does not induce refolding.     

Characterization of an abnormal fibrinogen Osaka V with the replacement of gamma-arginine 375 by glycine. The lack of high affinity calcium binding to D-domains and the lack of protective effect of calcium on fibrinolysis.

Prolonged thrombin time was completely corrected by the addition of millimolar concentrations of calcium in a new abnormal fibrinogen, Osaka V. Analysis of lysyl endopeptidase digests of A alpha-, B beta-, or gamma-chains by high performance liquid chromatography, and the following amino acid sequence analysis of relevant peptides revealed that about 50% of the gamma-chain has a replacement of gamma-arginine 375 by glycine. When fibrinogen was digested with plasmin in the presence of millimolar concentration of calcium, the amount of fragment D1 was about 50% of the normal control, and the rest was further cleaved to fragment D2, D3, or D62 with an apparent Mr of 62,000. Plasmic digestion of cross-linked fibrin in the presence of calcium resulted in the appearance of an abnormal fragment with an apparent Mr of 123,000 as well as fragments D2, D3, and D62, concomitant with the decrease of D dimer. The gamma-remnant of the abnormal fragment proved to be a cross-linked complex of the normal D1 gamma-remnant and residues 374-406/411 of the abnormal gamma-chain. The number of high affinity Ca(2+)-binding sites for the normal fibrinogen and fibrinogen Osaka V obtained by equilibrium dialysis was 2.88 (about 3) and 1.85, respectively, and that for the abnormal molecules was calculated as 0.9 (about 1) from their relative amounts in the samples, suggesting the lack of two Ca(2+)-binding sites in the D-domains. These data suggest that the normal structure of the COOH-terminal portion of the gamma-chain including residue 375 is required for the full expression of high affinity calcium binding to D-domains, the ability to be protected by calcium against plasmic digestion, and fibrin polymerization. During these studies, we found that the NH2-terminal amino acid of the gamma-remnant in fragments D or D dimer which were obtained after prolonged digestion with plasmin is gamma-Met89.     

Purification of achatin-I from the atria of the African giant snail, Achatina fulica, and its possible function.

Achatin-I previously purified from the ganglia of the African giant snail Achatina fulica was isolated from the atria of this snail. Achatin-I appeared to enhance the cardiac activity in two ways; centrally this peptide increased impulse frequency and produced spike broadening of the identified heart excitatory neuron, PON, and peripherally it enhanced amplitude and frequency of the heart beat. Achatin-I showed excitatory actions not only on the heart but on several other muscles.     

Presence of 2-methyl-6,7-dihydroxy-1,2,3,4-tetrahydroisoquinoline and 1,2-dimethyl-6,7-dihydroxy-1,2,3,4-tetrahydroisoquinoline, novel endogenous amines, in parkinsonian and normal human brains

2-Methyl-6,7-dihydroxy-1,2,3,4-tetrahydroisoquinoline and 1,2-dimethyl-6,7-dihydroxy-1,2,3,4-tetrahydroisoquinoline were identified for the first time as novel endogenous amines in parkinsonian and normal human brains by gas chromatography-mass spectrometry. It is of interest that these tetrahydroisoquinolines are analogues of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) which produces Parkinson's disease.     

Prevalence of spotted fever group rickettsia antibody in Apodemus speciosus captured in an endemic focus in Miyazaki Prefecture, Japan

Fourteen of Apodemus speciosus (large Japanese field mouse) were captured near the place where one of the patients with spotted fever group rickettsiosis had been infected, in Takaoka town, Miyazaki Prefecture. In the town, four human cases were reported. All of the mice had antibodies against Rickettsia japonica and R. montana. The incidence of the antibody was significantly higher in Apodemus mice in the area than in those from nonendemic area.