Febs Letters

doi: 10.1016/0014-5793(86)81212-1pmid: N/A

Lucy, Jack A.; Ahkong, Quet F.

doi: 10.1016/0014-5793(86)81213-3pmid: 3007213

A molecular model for fusion‐fission reactions in membranes is proposed that is based on data from studies on artificially induced cell fusion and on the behaviour of phospholipid bilayers: it is put forward as a framework for further investigations into this fundamental property of biological systems.

Lancaster, J.R.

doi: 10.1016/0014-5793(86)81214-5pmid: N/A

Due primarily to considerations of the nature of the electron transfer reactions which drive ATP synthesis in the methanogenic bacteria, substrate‐level phosphorylation (SLP) has been generally ruled out. Recent studies, however, have cast doubt on an obligatory role for a transmembrane ion gradient in coupling. In this paper, a scheme is proposed for SLP coupled to methane formation. The essential features are phosphorylation of bound C1 intermediate coupled to intermolecular electron transfer in a multifunctional protein complex containing a collection of bound C1 and electron carriers. ATP synthesis is accomplished by subsequent phosphoryl transfer. The scheme is analogous to all known mechanisms of SLP and is compatible with most of the data published to date.

Premereur, Noël; Van den Branden, Christiane; Roels, Frank

doi: 10.1016/0014-5793(86)81215-7pmid: 3956743

By administration of allylisopropylacetamide, an inhibitor of cytochrome P‐450, we demonstrated that cytochrome P‐450 is involved in the production of H2O2 during aminopyrine metabolism and phenobarbital induction in both the unanaesthetized guinea pig and rat. In the guinea pig we also found evidence for the existence of a basal cytochrome P‐450‐dependent H2O2 production, i.e. in the absence of exogenous substrate. Catalase participates in the decomposition of H2O2 produced in the endoplasmic reticulum where cytochrome P‐450 is localized.

Schoeder, H.-U.; Lockau, W.

doi: 10.1016/0014-5793(86)81216-9pmid: N/A

Photosystem I preparations from the cyanobacterium Anabaena variabilis and from spinach were analyzed for their quinone content. The dominant quinone was identified as phylloquinone. It was present at a ratio of roughly 2 per P700 (the primary electron donor of photosystem I) both in particles prepared with Triton X‐100 and on the large, P700‐carrying subunit derived from these particles by treatment with SDS. The results suggest a function of phylloquinone in the reaction center.

Linse, Sara; Drakenberg, Torbjörn; Forsén, Sture

doi: 10.1016/0014-5793(86)81217-0pmid: 3956744

113Cd‐NMR studies of solutions of cadmium‐loaded calmodulin (Cd4CaM) and the tetradecapeptide mastoparan in different ratios show that mastoparan binds to Cd4CaM with high affinity. The off‐rate of proteinbound mastoparan is found to be 40 s−1 or less. The binding of one molecule of mastoparan to Cd4CaM is observed to affect all four metal‐binding sites, indicating that both the N‐terminal and C‐terminal globular domains of the protein undergo conformational changes.

Roux, Michel; Neumann, Jean-Michel

doi: 10.1016/0014-5793(86)81218-2pmid: 3956745

Head‐group deuterated 1,2‐dimyristoyl‐sn‐glycero‐3‐phosphorylserine (DMPS) was synthesized. 2H NMR spectra reflect the ionic strength‐dependent polymorphism of DMPS aqueous dispersions. Results obtained with pure DMPS and mixed bilayers with phosphatidylcholine or phosphatidylethanolamine at various NaCl or LiCl concentrations indicate that interactions with Na+ and Li+ have very different effects upon the head‐group quadrupole splittings.

Simmaco, Maurizio; John, Robert A.; Barra, Donatella; Bossa, Francesco

doi: 10.1016/0014-5793(86)81219-4pmid: 3754226

Tentative assignments of functional residues in rat liver mitochondrial ornithine aminotransferase have recently been made using the amino acid sequence deduced from a cDNA clone [(1985) J.Biol.Chem. 260, 12993‐12997]. Partial sequences obtained using the pure mature protein demonstrate that one of these assignments, that of Lys 292 as the residue that binds the coenzyme pyridoxal phosphate, is correct. However, the identification of the Glu 34‐Gln 35 bond as the site of post‐translational proteolysis is in error. This cleavage occurs instead at Ala 25‐Thr 26.

Seemüller, Ursula; Arnhold, Marianne; Fritz, Hans; Wiedenmann, Karin; Machleidt, Werner; Heinzel, Regina; Appelhans, Heribert; Gassen, Hans-Günter; Lottspeich, Friedrich

doi: 10.1016/0014-5793(86)81220-0pmid: 3485543

The complete amino acid sequence of human antileukoprotease has been determined by direct sequencing of the inhibitory active protein isolated from seminal plasma (HUSI‐I) and by sequence analysis of cDNA reverse‐transcribed from mRNA prepared from cervical tissue. The inhibitor (M r 11 726) consists of 107 amino acid residues including 16 cysteines presumably forming disulfide bonds. The molecule comprises two consecutive domains which are homologous to each other, to the second domain of the basic protease inhibitor from Red Sea turtle (chelonianin) and to both domains of the whey proteins of rat and mouse. Both domains contain a pattern of cysteines known as the ‘four‐disulfide‐core’ that has also been found in wheat germ agglutinin and neurophysin.

Murakami, Yasuko; Marumo, Miya; Hayashi, Shin-ichi

doi: 10.1016/0014-5793(86)81221-2pmid: 3956746

It has been reported that ‘antizyme’, a protein inhibitor of ornithine decarboxylase (ODC) induced by its product, is not found in rat or mouse kidney. We determined whether antizyme was present in rabbit kidney cells (RK13) in culture. Antizyme could be induced in these cells by putrescine treatment, a substantial portion being in the particulate fraction in contrast with hepatic antizyme. Furthermore, ODC‐antizyme complex was present even in untreated cells. Pretreatment of cells with putrescine increased the relative amount of ODC‐antizyme complex and accelerated decay of ODC. These results support the ubiquitous existence of antizyme and its role in ODC degradation.