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31.
Recent studies have provided evidence that peptides as short as tripeptides do adopt preferred conformations. Here we report that the tripeptide Ala-Phe-Ala (AFA) in aqueous solution preferentially forms an inverse gamma-turn. Circular dichroism (CD) indicated the presence of a predominant turn structure, and Fourier transform infrared (FTIR) bands suggested the presence of a gamma-turn forming a bifurcated H-bond with the solvent molecules. The high-resolution structure was obtained by a combined use of NMR spectroscopy and calculations. On the basis of 30 unambiguous ROESY-derived distance restraints (including the Halpha-NH NOE between Ala(1) and Ala(3) and a hydrogen bond between the CO group of Ala(1) and the NH group of Ala(3)), calculations clearly demonstrated the presence of an inverse gamma-turn centered on Phe(2). From NOE data, we estimated a mole fraction for the gamma-turn of 0.65. Since for AFA an extended beta-strand was also reported [Eker, F., Griebenow, K., Cao, X., Nafie, L. A., and Schweitzer-Stenner, R. (2004) Proc. Natl. Acad. Sci. U.S.A. 101, 10054-10059], we investigated the possibility that gamma-turn and beta-strand may represent two major conformations. By using a best-fit procedure that calculated experimental NOEs as weighted averages of the effects originating from both structures, we were able to calculate with good accuracy the backbone NOEs at 280 K in terms of the two limiting conformers, yielding a mole fraction for the gamma-turn and beta-strand conformations of 0.60 and 0.40, respectively, in good agreement with those found by NOE data. The implication of the existence of a preferred conformation by a small structural element is discussed in the context of the nucleation of protein folding events and the design of small peptide and peptidomimetic drugs. 相似文献
32.
Azzolini SS Santos JM Souza AF Torquato RJ Hirata IY Andreotti R Tanaka AS 《Experimental parasitology》2004,106(3-4):103-109
The fly Haematobia irritans irritans is one of the most important ectoparasites in cattle production, due to its ability to suck large amounts of blood. This report describes the purification and characterization of a serine proteinase inhibitor (HiTI) present in H. i. irritans head and thorax extracts. The HiTI purified by affinity chromatography on trypsin-Sepharose has a molecular mass of 7029Da by MALDI-TOF mass spectrometry. HiTI inhibited bovine trypsin, human neutrophil elastase, and a trypsin-like enzyme purified from H. i. irritans abdomen with dissociation constants of 0.57, 1.30, and 0.20nM, respectively. The HiTI partial amino acid sequence allowed its classification into the BPTI-Kunitz-type family. An HiTI cDNA fragment was cloned in the pGEMT vector using RT-PCR. The translated amino acid sequence of HiTI cDNA confirmed a unique Kunitz-type-domain protein. Our results suggest that HiTI could control some endogenous enzyme, e.g., the H. i. irritans trypsin-like protein. 相似文献
33.
Regaya I Beeton C Ferrat G Andreotti N Darbon H De Waard M Sabatier JM 《The Journal of biological chemistry》2004,279(53):55690-55696
Maurotoxin (MTX) and HsTx1 are two scorpion toxins belonging to the alpha-KTx6 structural family. These 34-residue toxins, cross-linked by four disulfide bridges, share 59% sequence identity and fold along the classical alpha/beta scaffold. Despite these structural similarities, they fully differ in their pharmacological profiles. MTX is highly active on small (SK) and intermediate (IK) conductance Ca(2+)-activated (K(+)) channels and on voltage-gated Kv1.2 channel, whereas HsTx1 potently blocks voltage-gated Kv1.1 and Kv1.3 channels only. Here, we designed and chemically produced MTX-HsTx1, a chimera of both toxins that contains the N-terminal helical region of MTX (sequence 1-16) and the C-terminal beta-sheet region of HsTx1 (sequence 17-34). The three-dimensional structure of the peptide in solution was solved by (1)H NMR. MTX-HsTx1 displays the activity of MTX on SK channel, whereas it exhibits the pharmacological profile of HsTx1 on Kv1.1, Kv1.2, Kv1.3, and IK channels. These data demonstrate that the helical region of MTX exerts a key role in SK channel recognition, whereas the beta-sheet region of HsTx1 is crucial for activity on all other channel types tested. 相似文献
34.
Regaya I Pham T Andreotti N Sauze N Carrega L Martin-Eauclaire MF Jouirou B Peragut JC Vacher H Rochat H Devaux C Sabatier JM Guieu R 《Life sciences》2004,76(4):367-377
It has been shown that A2A adenosine receptors are implicated in pain modulation. The precise mechanism by which activation of A2A receptors produces analgesic effects, however, remains unclear. The aim of this study was to investigate the possible involvement of apamin-sensitive calcium-activated potassium channels (SKCa) and voltage-gated potassium (Kv) channels in A2A receptor activation-induced analgesic effects. Using mice, we evaluated the influence of apamin, a non specific blocker of SKCa channels, Lei-Dab7 (an analog of scorpion Leiurotoxin), a selective blocker of SKCa2 channels, and kaliotoxin (KTX) a Kv channel blocker, on the CGS 21680 (A2A adenosine receptor agonist)-induced increases in hot plate and tail pinch latencies. All drugs were injected in mice via the intracerebroventricular route. We found that apamin and Lei-Dab7, but not KTX, reduced antinociception produced by CGS21680 on the hot plate and tail pinch tests in a dose dependent manner. Lei-Dab 7 was more potent than apamin in this regard. We conclude that SKCa but not Kv channels are implicated in CGS 21680-induced antinociception. 相似文献
35.
Poillot C Bichraoui H Tisseyre C Bahemberae E Andreotti N Sabatier JM Ronjat M De Waard M 《The Journal of biological chemistry》2012,287(21):17331-17342
Maurocalcine is the first demonstrated example of an animal toxin peptide with efficient cell penetration properties. Although it is a highly competitive cell-penetrating peptide (CPP), its relatively large size of 33 amino acids and the presence of three internal disulfide bridges may hamper its development for in vitro and in vivo applications. Here, we demonstrate that several efficient CPPs can be derived from maurocalcine by replacing Cys residues by isosteric 2-aminobutyric acid residues and sequence truncation down to peptides of up to 9 residues in length. A surprising finding is that all of the truncated maurocalcine analogues possessed cell penetration properties, indicating that the maurocalcine is a highly specialized CPP. Careful examination of the cell penetration properties of the truncated analogues indicates that several maurocalcine-derived peptides should be of great interest for cell delivery applications where peptide size matters. 相似文献
36.
Marcos Valerio Garcia Vinicius da Silva Rodrigues Antônio Carlos Monteiro Lucas Detogni Simi Leandro de Oliveira Souza Higa Maria Marlene Martins Nancy Prette Dinalva Alves Mochi Renato Andreotti Matias Pablo Juan Szabó 《Experimental & applied acarology》2018,76(4):507-512
Amblyomma parvum Aragão (Acari: Ixodidae) is a tick species found with wide distribution in the Neotropical region. Even though it is a wildlife-related tick, it is also a frequent parasite of domestic animals, is aggressive to human beings and may harbor pathogenic microorganisms. Therefore, it is a target species for control on domestic animals, particularly those at the rural–wildlife interface. Herein, the efficacy of two isolates (E9 and IBCB 425) of an entomopathogenic fungus, Metarhizium anisopliae sensu lato, already evaluated for ticks that parasitize domestic animals, was tested against unfed A. parvum adults. Both isolates displayed high acaricidal efficacy after immersion in fungal conidial suspensions for 5 min. Isolate E9 killed all ticks by the 7th day post-treatment, and isolate IBCB 425 did so by the 11th day. Tick mortality of 80 and 90% was achieved as early as the 3rd and 4th days, respectively, with both treatments. Thus, if a commercial M. anisopliae s.l. acaricide against domestic animal ticks is developed, it would also be effective against A. parvum. 相似文献
37.
Retrotransposon BARE-1 and Its Role in Genome Evolution in the Genus Hordeum. 总被引:11,自引:0,他引:11
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CM Vicient A Suoniemi K Anamthawat-Jnsson J Tanskanen A Beharav E Nevo AH Schulman 《The Plant cell》1999,11(9):1769-1784
38.
Xiao Ding Xuedong Dai Kai Long Cheng Peng Daniele Andreotti Paul Bamborough Andrew J. Eatherton Colin Edge Karamjit S. Jandu Paula L. Nichols Oliver J. Philps Luigi Piero Stasi Zehong Wan Jia-Ning Xiang Kelly Dong Pamela Dossang Ming-Hsun Ho Yi Li Feng Ren 《Bioorganic & medicinal chemistry letters》2017,27(17):4034-4038
Leucine-rich repeat kinase 2 (LRRK2) has been suggested as a potential therapeutic target for Parkinson’s disease. Herein we report the discovery of 5-substituent-N-arylbenzamide derivatives as novel LRRK2 inhibitors. Extensive SAR study led to the discovery of compounds 8e, which demonstrated potent LRRK2 inhibition activity, high selectivity across the kinome, good brain exposure, and high oral bioavailability. 相似文献
39.
Aurlie Bocquier Pierre Verger Arnaud Basdevant Grard Andreotti Jean Baretge Patrick Villani Alain Paraponaris 《Obesity (Silver Spring, Md.)》2005,13(4):787-795
Objective: To describe the current knowledge, attitudes, and practices of French general practitioners (GPs) in the field of adult overweight and obesity management. Research Methods and Procedures: A cross‐sectional telephone survey interviewed a sample of 600 GPs, representative of the private GPs in southeastern France. A four‐part questionnaire assessed personal and professional characteristics, attitudes and opinions about overweight and obesity, relevant knowledge and training, and practices (diagnostic methods, clinical assessments, weight loss objectives, types of counseling). Results: Most GPs knew that weight problems are health‐threatening, and 79% agreed that managing these problems is part of their role. Nevertheless, 58% did not feel they perform this role effectively, and one‐third did not find it professionally gratifying. Approximately 30% had negative attitudes toward overweight and obese patients; 57% were pessimistic about patients’ ability to lose weight; 64% often set weight loss objectives more demanding than guidelines call for; and neither food diaries nor nutritional education were used systematically. GPs’ feelings of effectiveness and attitudes toward obese patients were associated with some professional (training) and personal (BMI, personal diet experience) characteristics. Discussion: GPs’ feelings of ineffectiveness may stem from an underlying conflict between practitioners’ and patients’ representations of weight problems and the relationship problems this causes. Inadequate practices and health care system organization may also play a role. 相似文献
40.