Febs Letters

Subirana, Juan A; Palau, Jaume

doi: 10.1016/S0014-5793(99)00310-5pmid: 10217397

Single amino acid repeats are found in different kinds of proteins. Some of these repeats are pathogenic. It is striking that some amino acids are able to form such repeats, but other amino acids are not. We suggest an explanation for this fact based on the different tendency of each amino acid to form aggregates. Aggregation may be due to the formation of incipient lamellar crystals as they have been described in poly‐α‐amino acids and in most synthetic polymers.

Jennings, B.J.; Ozanne, S.E.; Dorling, M.W.; Hales, C.N.

doi: 10.1016/S0014-5793(99)00336-1pmid: 10217398

Maternal protein undernutrition can influence the growth and longevity of male offspring in the rat. We tested the hypothesis that these differences in longevity were associated with changes in the rate of telomere shortening. We found age‐related shortening of telomeres in the liver and kidney but not in the brain of male rats. Growth retardation in postnatal life was associated with significantly longer kidney telomeres and an increased longevity. Conversely, growth retardation during the foetal life followed by postnatal catch‐up growth was associated with a shorter life span and shorter kidney telomeres. These findings may provide a mechanistic basis for epidemiological studies linking early growth retardation to adult degenerative diseases.

Bugno, Marcin; Witek, Barbara; Bereta, Joanna; Bereta, Michal; Edwards, Dylan R.; Kordula, Tomasz

doi: 10.1016/S0014-5793(99)00323-3pmid: 10217399

Cytokine‐dependent regulation of tissue inhibitors of metalloproteinases (TIMPs) expression provides an important mechanism for controlling the activity of matrix metalloproteinases. We present data indicating that during inflammatory processes TIMP‐1 and TIMP‐3 may be involved in the proteolytic remodeling of subendothelial basement membrane of the brain microvascular system, a key step during leukocyte migration into the brain perivascular tissue. In brain endothelial cells the expression of TIMP‐1 is dramatically up‐regulated by major proinflammatory cytokines, with the combination of interleukin‐1β (IL‐1β) and tumor necrosis factor‐α (TNFα) exhibiting the strongest synergistic stimulation. Simultaneously, IL‐1β/TNFα almost completely blocks TIMP‐3 expression. Both synergistic effects are dose‐dependent within the concentration range 0.05–5 ng/ml of both cytokines and correlate with the expression of inducible nitric oxide synthase, an endothelial cell activation marker. Down‐regulation of TIMP‐3 expression is also detected in astrocytes treated with TNFα or IFN‐γ, whereas oncostatin M as well as TNFα up‐regulate TIMP‐1 mRNA level. We propose that the cytokine‐modified balance between TIMP‐1 and TIMP‐3 expression provides a potential mechanism involved in the regulation of microvascular basement membrane proteolysis.

Rourke, Ian J; Hansen, Thomas vO; Nerlov, Claus; Rehfeld, Jens F; Nielsen, Finn C

doi: 10.1016/S0014-5793(99)00320-8pmid: 10217400

The promoter of the cholecystokinin (CCK) gene possesses evolutionary conserved juxtaposed E‐box and cAMP/TPA responsive elements (CRE/TRE). We have examined the functional interaction of these two sites. As previously noted, c‐Jun/c‐Fos heterodimers greatly increase promoter activity through association with the CRE/TRE. Mutation of the E‐box enhanced the activation by c‐Jun/c‐Fos, as well as stimulation by forskolin and bFGF, that acts through the CRE/TRE site. Moreover, c‐Jun/c‐Fos stimulation was inhibited by co‐expression of c‐Myc and Max. The results indicate that factors associating with the E‐box exhibit a negative cooperative effect on the activation via the CRE/TRE element. We propose that this mechanism plays a significant role in CCK gene transcription and other genes with juxtaposed E‐box and CRE/TRE.

Gomez de Cedrón, Marta; Ehsani, Neda; Mikkola, Marja L.; Garcı́a, Juan Antonio; Kääriäinen, Leevi

doi: 10.1016/S0014-5793(99)00321-Xpmid: 10217401

Semliki Forest virus replicase protein nsP2 shares sequence homology with several putative NTPases and RNA helicases. NsP2 has RNA‐dependent NTPase activity. Here we expressed polyhistidine‐tagged nsP2 in Escherichia coli, purified it by metal‐affinity chromatography, and used it in RNA helicase assays. RNA helicase CI of plum pox potyvirus was used as a positive control. Unwinding of α‐32P‐labelled partially double‐stranded RNA required nsP2, Mg2+ and NTPs. NsP2 with a mutation, K192N, in the NTP‐binding sequence GVPGSGK192SA could not unwind dsRNA and had no NTPase activity. This is the first demonstration of RNA helicase activity within the large alphavirus superfamily.

Zhang, Hong; Heim, Jutta; Meyhack, Bernd

doi: 10.1016/S0014-5793(99)00335-Xpmid: 10217402

By PCR and EST database searches we have identified three novel BNIP1 splice variants, and found that one of them, BNIP1‐b, contains a highly conserved BH3 domain. The BNIP1 gene has been assigned to chromosome 5q33–34. Using in vitro protein‐protein interaction assays, all BNIP1 variants were shown to interact with BCL2 and also with BCL2L1 (previously Bcl‐xL). These interactions are BH3‐independent. Furthermore, the BNIP1 variants cannot interact with BAX. The results suggest that the BNIP1 variants are novel members of the BCL2 family but function through a mechanism different from other BH3‐only members.

Chams, Vida; Bonnafous, Pierre; Stegmann, Toon

doi: 10.1016/S0014-5793(99)00333-6pmid: 10217403

The influence of a hydrophilic layer covering the membrane on influenza hemagglutinin (HA) mediated fusion was investigated using membranes containing poly(ethylene‐glycol) grafted phosphatidylethanolamine (PEG‐2000‐PE). Steric inhibition of HA‐membrane interactions by these lipids affected virus fusion (half‐maximal inhibition at 0.8 mol% for lipids with 114 ethylene glycol residues, or at 3.2 mol% for 45 residues (PEG‐2000‐PE), concentrations at which the PEG moieties adopt a random coil structure). Reconstituted viral membranes containing 3 mol% PEG‐2000‐PE retained 40% of their fusion activity. Therefore, efficient fusion is possible with membranes completely covered by a hydrophilic layer of several nanometers, and fusogenic virosomes containing PEG‐PE are feasible.

Mine, Shouhei; Ueda, Tadashi; Hashimoto, Yoshio; Tanaka, Yoshitsugu; Imoto, Taiji

doi: 10.1016/S0014-5793(99)00332-4pmid: 10217404

The non‐enzymatic deamidation of Asn to Asp is known to occur in proteins and peptides and is accelerated by phosphate buffer [Tyler‐Cross, R. and Schirch, V. (1991) J. Biol. Chem. 25, 22549–22556]. We attempted to identify the site in lysozyme where a phosphate ion binds by means of 1H‐15N HSQC measurements of 15N‐labeled lysozyme, which was successfully obtained using Pichia pastoris. As a result, we found that the phosphate ion was preferentially bound to Asn‐103 in hen lysozyme. The method presented here may be useful for identifying the binding site of a protein with low molecular weight substances.

Zheleznaya, Lyudmila; Shiryaev, Sergey; Zheleznyakova, Elena; Nadezhda Matvienko, ; Matvienko, Nicholas

doi: 10.1016/S0014-5793(99)00330-0pmid: 10217405

The strain Staphylococcus species D5 produces a restriction enzyme. It is the neoschizomer of HphI endonuclease, which cleaves DNA at a distance of eight nucleotides from the recognition sequences producing blunt end DNA fragments: 5′‐GGTGA8N↓‐3′ and 3′‐CCACT8N↑‐5′.

Ogawa, Masahiro; Nakamura, Soichiro; Atsuchi, Tetsumori; Tamiya, Toru; Tsuchiya, Takahide; Nakai, Shuryo

doi: 10.1016/S0014-5793(99)00327-0pmid: 10217406

A cDNA encoding achacin, an antimicrobial glycoprotein from the body surface mucus of giant African snail Achacina fulica Férussac, was expressed in a methylotrophic yeast, Pichia pastoris, and recombinant achacin (rAch) was secreted in yeast minimal medium in a polyglycosylated form with 80 kDa. Carbohydrate analysis revealed that the glycosylated moiety of rAch was composed of 50 mol mannose and 2 mol N‐acetylglucosamine residues. Antimicrobial activity using Escherichia coli and Staphylococcus aureus showed that the rAch had a behavior similar to its native counterpart. The rAch showed so wide an antimicrobial spectrum that 0.1 mg/ml rAch inhibited the growth of Pseudomonas fluorescens, Staphylococcus epidermidis, and Streptococcus faecalis in addition to E. coli and S. aureus, whereas it did not appreciably affect the growth of Proteus mirabilis, Bacillus cereus and Micrococcus luteus. The rAch was also effective in preventing growth of Vibrio anguillarum and Vibrio parahaemolyticus. The results suggested that the rAch had great potential of using as an antimicrobial agent.