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Chemical and biological reactivity in interfaces

Grant number: 07/50970-5
Support type:Research Projects - Thematic Grants
Duration: October 01, 2007 - September 30, 2012
Field of knowledge:Biological Sciences - Biophysics - Molecular Biophysics
Cooperation agreement: NSF - American Universities (Chemistry)
Principal Investigator:Hernan Chaimovich Guralnik
Grantee:Hernan Chaimovich Guralnik
Principal investigator abroad: Daniel Talham
Institution abroad: University of Florida, Gainesville (UF), United States
Home Institution: Instituto de Química (IQ). Universidade de São Paulo (USP). São Paulo , SP, Brazil
Co-Principal Investigators:Iolanda Midea Cuccovia


Fundamental and applied research in bio-mimetic systems, using micelles and vesicles as models, is the focus of our line. We study structure of aggregates, catalytic properties of micelles and vesicles, mechanism of chemical reactions and protein/membrane interaction. Of these contributions, we should highlight (Magazine, year, quotation): vesicles prepared with phosphate diester (BBRC, 1978, 98); thiolisis in micelles (JOC, 1978, 19); method of quantitative analysis of kinetics in micelles and vesicles (JPC, 1979, 349); pH in interfaces (JPC, 1980, 84); pK apparent in membranes (BBA, 1984, 67) activity of water in reverse micelles (JPC, 1986, 63); plant uncoupling mitochondrial protein (Nature, 1995, 133); water in the micelles interface (Langmuir, 2000, 61). In this project we will use various methods, especially chemical capture, to research the bonding of ions to micelles and vesicles, since this parameter determines structure and function of these aggregates. The bonding of ions in zwitteronic micelles, and of poorly reactive ions in micelles, the degree of internal and external dissociation of vesicles, mechanism of micellization of charged detergents and of mixtures with zwitteronics constitute the themes of this chapter. New structural, rheological and functional properties of micelles will be studied with derivatives of triflate of alquil trimethylammonium and amphipathic polymers. Chemical reactions (hydrolysis of phosphates and thiolisis) and a new scale of nucleophilicity (using reactions of phenyldiazonium) will be explored. The study of phosphate triester oximolysis will be analyzed with the aim of obtaining new systems of treatment for skin contaminated by insecticides and chemical weapons. The interaction of peptides with bilayers will be investigated using kinetics of leakage from liposomes and calorimetry. The modification of the enzymatic activity by interaction with detergents and other amphiphilics will be investigated using proteases and phosphatases as model. (AU)

Scientific publications (6)
(References retrieved automatically from Web of Science and SciELO through information on FAPESP grants and their corresponding numbers as mentioned in the publications by the authors)
MANZINI, MARIANA C.; PEREZ, KATIA R.; RISKE, KARIN A.; BOZELLI, JR., JOSE C.; SANTOS, TALITA L.; DA SILVA, MARCIA A.; SARAIVA, GREICE K. V.; POLITI, MARIO J.; VALENTE, ANA P.; ALMEIDA, FABIO C. L.; CHAIMOVICH, HERNAN; RODRIGUES, MAGALI A.; BEMQUERER, MARCELO P.; SCHREIER, SHIRLEY; CUCCOVIA, IOLANDA M. Peptide:lipid ratio and membrane surface charge determine the mechanism of action of the antimicrobial peptide BP100. Conformational and functional studies. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES, v. 1838, n. 7, p. 1985-1999, JUL 2014. Web of Science Citations: 41.
LIMA, FILIPE S.; CHAIMOVICH, HERNAN; CUCCOVIA, IOLANDA M.; BUCHNER, RICHARD. Dielectric Relaxation Spectroscopy Shows a Sparingly Hydrated Interface and Low Counterion Mobility in Triflate Micelles. Langmuir, v. 29, n. 32, p. 10037-10046, AUG 13 2013. Web of Science Citations: 13.
LIMA, FILIPE S.; CUCCOVIA, IOLANDA M.; HORINEK, DOMINIK; AMARAL, LIA Q.; RISKE, KARIN A.; SCHREIER, SHIRLEY; SALINAS, ROBERTO K.; BASTOS, ERICK L.; PIRES, PAULO A. R.; BOZELLI, JR., JOSE CARLOS; FAVARO, DENIZE C.; RODRIGUES, ANA CLARA B.; DIAS, LUIS GUSTAVO; EL SEOUD, OMAR A.; CHAIMOVICH, HERNAN. Effect of Counterions on the Shape, Hydration, and Degree of Order at the Interface of Cationic Micelles: The Triflate Case. Langmuir, v. 29, n. 13, p. 4193-4203, APR 2 2013. Web of Science Citations: 21.
DE SOUZA, TEREZA PEREIRA; CHAIMOVICH, HERNAN; FAHR, ALFRED; SCHWEITZER, BIANCA; NETO, AUGUSTO AGOSTINHO; CUCCOVIA, IOLANDA MIDEA. Interfacial concentrations of chloride and bromide in zwitterionic micelles with opposite dipoles: Experimental determination by chemical trapping and a theoretical description. Journal of Colloid and Interface Science, v. 371, p. 62-72, APR 1 2012. Web of Science Citations: 5.
LIMA, F. S.; CHAIMOVICH, H.; CUCCOVIA, I. M. Kinetics and product distribution of p-nitrophenyl phosphate dianion solvolysis in ternary DMSO/alcohol/water mixtures are compatible with metaphosphate formation. JOURNAL OF PHYSICAL ORGANIC CHEMISTRY, v. 25, n. 1, p. 9-13, JAN 2012. Web of Science Citations: 4.
LIMA, F. S.; MAXIMIANO, F. A.; CUCCOVIA, I. M.; CHAIMOVICH, H. Surface Activity of the Triflate Ion at the Air/Water Interface and Properties of N,N,N-Trimethyl-N-Dodecylammonium Triflate Aqueous Solutions. Langmuir, v. 27, n. 8, p. 4319-4323, APR 19 2011. Web of Science Citations: 15.

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