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(Referência obtida automaticamente do Web of Science, por meio da informação sobre o financiamento pela FAPESP e o número do processo correspondente, incluída na publicação pelos autores.)

Enzyme Microheterogeneous Hydration and Stabilization in Supercritical Carbon Dioxide

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Autor(es):
Silveira, Rodrigo L. [1] ; Martinez, Julian [2] ; Skaf, Munir S. [1] ; Martinez, Leandro [3]
Número total de Autores: 4
Afiliação do(s) autor(es):
[1] Univ Estadual Campinas, Inst Chem, Campinas, SP - Brazil
[2] Univ Estadual Campinas, Fac Food Engn, Campinas, SP - Brazil
[3] Univ Sao Paulo, Inst Phys Sao Carlos, Sao Carlos, SP - Brazil
Número total de Afiliações: 3
Tipo de documento: Artigo Científico
Fonte: Journal of Physical Chemistry B; v. 116, n. 19, p. 5671-5678, MAY 17 2012.
Citações Web of Science: 26
Resumo

Supercritical carbon dioxide is a promising green-chemistry solvent for many enzyme-catalyzed chemical reactions, yet the striking stability of some enzymes in such unconventional environments is not well understood. Here, we investigate the stabilization of the Candida antarctica Lipase B (CALB) in supercritical carbon dioxide-water biphasic systems using molecular dynamics simulations. The preservation of the enzyme structure and optimal activity depend on the presence of small amounts of water in the supercritical dispersing medium. When the protein is at least partially hydrated, water molecules bind to specific sites on the enzyme surface and prevent carbon dioxide from penetrating its catalytic core. Strikingly, water and supercritical carbon dioxide cover the protein surface quite heterogeneously. In the first solvation layer, the hydrophilic residues at the surface of the protein are able to pin down patches of water, whereas carbon dioxide solvates preferentially hydrophobic surface residues. In the outer solvation shells, water molecules tend to cluster predominantly on top of the larger water patches of the first solvation layer instead of spreading evenly around the remainder of the protein surface. For CALB, this exposes the substrate-binding region of the enzyme to carbon dioxide, possibly facilitating diffusion of nonpolar substrates into the catalytic funnel. Therefore, by means of microheterogeneous solvation, enhanced accessibility of hydrophobic substrates to the active site can be achieved, while preserving the functional structure of the enzyme. Our results provide a molecular picture on the nature of the stability of proteins in nonaqueous media. (AU)

Processo FAPESP: 10/08680-2 - Aspectos moleculares da degradação de biomassa lignocelulósica: dinâmica de enzimas e nanoarquitetura de paredes celulares de plantas
Beneficiário:Rodrigo Leandro Silveira
Linha de fomento: Bolsas no Brasil - Doutorado
Processo FAPESP: 10/16947-9 - Estrutura, dinâmica e função em proteínas: simulação computacional e desenvolvimento de algoritmos
Beneficiário:Leandro Martinez
Linha de fomento: Auxílio à Pesquisa - Regular