title: Pressure induces folding intermediates that are crucial for protein-DNA recognition and virus assembly.
abstract: Protein-nucleic acid interactions are crucial for a variety of fundamental biological processes such as replication, transcription, restriction, translation and virus assembly. The molecular basis of protein-DNA and protein-RNA recognition is deeply related to the thermodynamics of the systems. We review here how protein-nucleic acid interactions can be approached in the same way as protein-protein interactions involved in protein folding and protein assembly, using hydrostatic pressure as the primary tool and employing several spectroscopic techniques, especially fluorescence, circular dichroism and high-resolution nuclear magnetic resonance. High pressure has the unique property of stabilizing partially folded states or molten-globule states of a protein. The competition between correct folding and misfolding, which in many proteins leads to formation of insoluble aggregates is an important problem in the biotechnology industry and in human diseases such as amyloidosis, Alzheimer's, prion and tumor diseases. The pressure studies reveal that a gradient of partially folded (molten globule) conformations is present between the unfolded and fully folded structure of several bacteria, plant and mammalian viruses. Using pressure, we have detected the presence of a ribonucleoprotein intermediate, where the coat protein is partially unfolded but bound to RNA. These intermediates are potential targets for antiviral compounds. Pressure studies on viruses have direct biotechnological applications. The ability of pressure to inactivate viruses has been evaluated with a view toward the applications of vaccine development and virus sterilization. Recent studies demonstrate that pressure causes virus inactivation while preserving the immunogenic properties. There is substantial evidence that a high-pressure cycle traps a virus in the 'fusion intermediate state', not infectious but highly immunogenic.
authors: Programa de Biologia Estrutural, Departamento de Bioquímica Médica - ICB, Centro Nacional de Ressonância Magnética Nuclear de Macromoléculas, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil. jerson@bioqmed.ufrj.br
authors: Jerson L
authors: JL
authors: Silva
authors: Andréa C
authors: AC
authors: Oliveira
authors: Andre M O
authors: AM
authors: Gomes
authors: Luís Maurício T R
authors: LM
authors: Lima
authors: Ronaldo
authors: R
authors: Mohana-Borges
authors: Ana B F
authors: AB
authors: Pacheco
authors: Débora
authors: D
authors: Foguel
mesh_terms: D000682:Amyloid / Q000737:chemistry / Q000302:isolation & purification; D000818:Animals; D004247:DNA / Q000737:chemistry*; D006801:Humans; D006874:Hydrostatic Pressure; D008561:Membrane Fusion / Q000502:physiology; D008958:Models, Molecular; D011487:Protein Conformation; D017510:Protein Folding; D011506:Proteins / Q000737:chemistry*; D019065:Virus Assembly / Q000502:physiology*
chemical_list: D000682:Amyloid; D011506:Proteins; D004247:DNA