Febs Letters

doi: 10.1016/0014-5793(92)81035-Kpmid: N/A

Stirk, H.J.; Woolfson, D.N; Hutchinson, E.G.; Thornton, J.M.

doi: 10.1016/0014-5793(92)81036-Lpmid: 1644197

The jellyroll structure is a special case of the Greek key topology and, to date, has only been observed in complete form in one of its four possible arrangements. Like other elements of super‐secondary structure involving the β‐strand (eg. the βαβ unit) the known structure forms a right‐handed superhelix. The possibility of losing such tertiary information and other problems associated with representing these structures by two‐dimensional topology diagrams are discussed. A series of rules are presented which allow this three‐dimensional information to be represented in two‐dimensional topology diagrams from which the handedness of a jellyroll structure can be determined.

Gordeuk, Victor R.; Brittenham, Gary M.

doi: 10.1016/0014-5793(92)81037-Mpmid: 1379550

Bleomycin‐reactive iron was detected in the sera of six out of nine adults undergoing intensive chemotherapy for acute non‐lymphocytic leukemia. In these individuals the corresponding transferrin saturation ranged from 96% to 113% and the serum ferritin from 775 to 9975 μg/l. Nontransferrin‐bound iron has been postulated to be a factor in organ toxicity in iron overload conditions such as beta thalassemia and hereditary hemochromatosis by facilitating the production of tissue‐damaging free radicals. We propose that bleomycin‐reactive iron should be considered as a possible factor in organ dysfunction seen with intensive cancer chemotherapy.

Niidome, Tetsuhiro; Kim, Man-Suk; Friedrich, Thomas; Mori, Yasuo

doi: 10.1016/0014-5793(92)81038-Npmid: 1379552

The complete amino acid sequence of a novel calcium channel (designated BII) from rabbit brain has been deduced by cloning and sequencing the cDNA. The BII calcium channel is structurally more closely related to the BI calcium channel than to the cardiac and skeletal muscle L‐type calcium channels. Blot hybridization analysis of RNA from different tissues and from different regions of the brain shows that the BII calcium channel is distributed predominantly in the brain, being abundant in the cerebral cortex, hippocampus and corpus striatum.

Vogel, Lotte Katrine; Norén, Ove; Sjöström, Hans

doi: 10.1016/0014-5793(92)81039-Opmid: 1353730

Human aminopeptidase N carries an apical sorting signal on its ectodomain necessary for its correct transport to the apical membrane in Madin‐Darby canine kidney cells. To determine whether the apical sorting signal is localized in the serine/threonine rich stalk or in the catalytic head group, anchor/stalk‐minus aminopeptidase N, consisting of the hemagglutinin signal peptide and the catalytic head group of human aminopeptidase N, was expressed in MDCK cells. Anchor/stalk‐minus aminopeptidase N was secreted mainly to the apical side. The catalytic head group of human aminopeptidase N thus carries an apical sorting signal.

Besson, Françoise; Michel, Georges

doi: 10.1016/0014-5793(92)81040-Spmid: 1644198

Bacillomycin D is an antifungal lipopeptide produced by B. subtilis. The formation of the peptidyl bonds of bacillomycin D occurs non‐ribosomally, as demonstrated by the use of chloramphenicol, an inhibitor of protein biosynthesis. Amino acid‐activating enzymes were found in B. subtilis cell lysates purified by affinity chromatography on a gel containing l‐Pro, an amino acid of bacillomycin D. Presence of ATP during this purification increases the binding of enzymatic proteins and their activity. An enzyme, with an apparent molecular weight of 230 kDa, catalyzed ATP‐PPi exchange reactions, which were mediated by specific amino acids, corresponding to a partial sequence of bacillomycin D.

Oguchi, Shinobu; Iida, Sachio; Adachi, Hiroko; Ohshima, Hiroshi; Esumi, Hiroyasu

doi: 10.1016/0014-5793(92)81041-Jpmid: 1379549

Ca2+/calmodulin‐dependent nitric oxide synthase was found to be induced during rat liver necrosis caused by administration of Propionibacterium acnes and E. coli lipopolysaccharide to rats. Examination of the specific induction of Ca2+/calmodulin‐dependent NO synthase showed that the enzyme was induced in the lung, spleen and colon as well as the liver. Northern blot analysis revealed that the induction occurred at the transcriptional level.

Herold, Marzell; Leistler, Bernd

doi: 10.1016/0014-5793(92)81042-Kpmid: 1644199

Equilibrium dissociation and unfolding of dimeric aspartate aminotransferase from Escherichia coli proceeds via two compact monomeric intermediates which have similar hydrodynamic volumes but different fluorescence properties. We probed binding of the coenzyme pyridoxal 5′‐phosphate to these intermediates by coupling fluorescence detection to size‐exclusion HPLC. This procedure gave additionally an internal conformational probe of the unfolding transitions of the enzyme. It was shown that the first intermediate, M, is able to bind the coenzyme, whereas the second intermediate, M, is not. It is likely that M is the correctly folded monomer of the protein.

Yutsudo, Takashi; Murai, Hitoshi; Gonzalez, Javier; Takao, Toshifumi; Shimonishi, Yasutsugu; Takeda, Yoshifumi; Igarashi, Hisanaga; Hinuma, Yorio

doi: 10.1016/0014-5793(92)81043-Lpmid: 1644200

A new type or mitogenic factor (protein) was purified from the culture supernatant of a strain of Streptococcus pyogenes by SP‐Sephadex C‐25 column chromatography, preparative isoelectric focusing and reversed‐phase high‐performance liquid chromatography. The purified factor, showing marked mitogenic activity in rabbit peripheral blood lymphocytes, gave a single‐band staining for protein an SDS‐PAGE, The molecular weight of the purified mitogenic factor was determined to be 25.370, which was different from those calculated from reported amino acid sequences deduced from 4 different nucleotide sequences of 3 kinds of streptococcal pyrogenic exotoxins (two SPEAs, SPEB and SPEC). The amino acid sequence of the N‐terminal region of the purified mitogenic factor was determined to be Gin‐Thr‐Gin‐Val‐Ser‐Asn‐Asp‐Val‐Val‐Leu‐Asn‐Asp‐Gly‐Ala‐Ser‐Lys‐Tyr‐Leu‐Asn‐Glu‐Ala‐, which was also different from the reported N‐terminal sequences deduced from the 4 different nucleotide sequences. These data indicate that this mitogenic factor is distinct from the already described streptococcal pyrogenic exotoxins.

Saeki, Yoshinaga; Ueno, Satoshi; Takahashi, Nobuyuki; Soga, Fumihisa; Yanagihara, Takehiko

doi: 10.1016/0014-5793(92)81044-Mpmid: 1644201

DNA sequence polymorphisms in transthyretin (TrR) genes were investigated by single‐strand conformation polymorphism (SSCP) analysis of polymerase chain reaction products. The amplified DNA fragments that encode each exon of the normal TTR gene showed two bands, representing the two complementary single strands of DNA. In one patient with amyloid polyneuropathy, the exon 3 DNA showed a unique, aberrant migration pattern. Direct sequencing analysis of the amplified exon 3 revealed a single base change (G‐to‐T), resulting in a novel amino acid substitution (Ser‐50 → Ile). We also present the SSCP patterns for five known Japanese TTR variants.