A hypothesis to reconcile the physical and chemical unfolding of proteins

被引:72
作者
de Oliveira, Guilherme A. P. [1 ]
Silva, Jerson L. [1 ]
机构
[1] Univ Fed Rio de Janeiro, Ctr Nacl Ressonancia Magnet Nucl Jiri Jonas, Inst Nacl Biol Estrutural & Bioimagem, Programa Biol Estrutural,Inst Bioquim Med Leopold, BR-21941590 Rio De Janeiro, Brazil
关键词
protein folding; hydrostatic pressure; urea; NMR; SAXS; HIGH-PRESSURE; X-RAY; ENERGY LANDSCAPE; STRUCTURAL-CHARACTERIZATION; UREA DENATURATION; HYDROGEN-BONDS; MUTANT P53; BINDING; PERTURBATION; DYNAMICS;
D O I
10.1073/pnas.1500352112
中图分类号
O [数理科学和化学]; P [天文学、地球科学]; Q [生物科学]; N [自然科学总论];
学科分类号
07 ; 0710 ; 09 ;
摘要
High pressure (HP) or urea is commonly used to disturb folding species. Pressure favors the reversible unfolding of proteins by causing changes in the volumetric properties of the protein-solvent system. However, no mechanistic model has fully elucidated the effects of urea on structure unfolding, even though proteinurea interactions are considered to be crucial. Here, we provide NMR spectroscopy and 3D reconstructions from X-ray scattering to develop the " push-and-pull" hypothesis, which helps to explain the initial mechanism of chemical unfolding in light of the physical events triggered by HP. In studying MpNep2 from Moniliophthora perniciosa, we tracked two cooperative units using HP-NMR as MpNep2 moved uphill in the energy landscape; this process contrasts with the overall structural unfolding that occurs upon reaching a threshold concentration of urea. At subdenaturing concentrations of urea, we were able to trap a state in which urea is preferentially bound to the protein (as determined by NMR intensities and chemical shifts); this state is still folded and not additionally exposed to solvent [fluorescence and small-angle X-ray scattering (SAXS)]. This state has a higher susceptibility to pressure denaturation (lower p(1/2) and larger Delta V-u); thus, urea and HP share concomitant effects of urea binding and pulling and water-inducing pushing, respectively. These observations explain the differences between the molecular mechanisms that control the physical and chemical unfolding of proteins, thus opening up new possibilities for the study of protein folding and providing an interpretation of the nature of cooperativity in the folding and unfolding processes.
引用
收藏
页码:E2775 / E2784
页数:10
相关论文
共 77 条
[61]   Pressure provides new insights into protein folding, dynamics and structure [J].
Silva, JL ;
Foguel, D ;
Royer, CA .
TRENDS IN BIOCHEMICAL SCIENCES, 2001, 26 (10) :612-618
[62]   DISSOCIATION OF A NATIVE DIMER TO A MOLTEN GLOBULE MONOMER - EFFECTS OF PRESSURE AND DILUTION ON THE ASSOCIATION EQUILIBRIUM OF ARC REPRESSOR [J].
SILVA, JL ;
SILVEIRA, CF ;
CORREIA, A ;
PONTES, L .
JOURNAL OF MOLECULAR BIOLOGY, 1992, 223 (02) :545-555
[63]   Free-Energy Linkage between Folding and Calcium Binding in EF-Hand Proteins [J].
Suarez, Marisa C. ;
Rocha, Cristiane B. ;
Sorenson, Martha M. ;
Silva, Jerson L. ;
Foguel, Debora .
BIOPHYSICAL JOURNAL, 2008, 95 (10) :4820-4828
[64]   Role of hydration in the closed-to-open transition involved in Ca2+ binding by troponin C [J].
Suarez, MC ;
Machado, CJV ;
Lima, LMTR ;
Smillie, LB ;
Pearlstone, JR ;
Silva, JL ;
Sorenson, MM ;
Foguel, B .
BIOCHEMISTRY, 2003, 42 (18) :5522-5530
[65]   DETERMINATION OF THE REGULARIZATION PARAMETER IN INDIRECT-TRANSFORM METHODS USING PERCEPTUAL CRITERIA [J].
SVERGUN, DI .
JOURNAL OF APPLIED CRYSTALLOGRAPHY, 1992, 25 :495-503
[66]  
Tanford C, 1970, Adv Protein Chem, V24, P1, DOI 10.1016/S0065-3233(08)60241-7
[67]   McVol - A program for calculating protein volumes and identifying cavities by a Monte Carlo algorithm [J].
Till, Mirco S. ;
Ullmann, G. Matthias .
JOURNAL OF MOLECULAR MODELING, 2010, 16 (03) :419-429
[68]   Implications of protein conformational diversity for binding and development of new biological active compounds [J].
Valente, A. P. ;
Miyamoto, C. A. ;
Almeida, F. C. L. .
CURRENT MEDICINAL CHEMISTRY, 2006, 13 (30) :3697-3703
[69]   A naturally occurring protective system in urea-rich cells: Mechanism of osmolyte protection of proteins against urea denaturation [J].
Wang, AJ ;
Bolen, DW .
BIOCHEMISTRY, 1997, 36 (30) :9101-9108
[70]   Concentration dependence of the subunit association of oligomers and viruses and the modification of the latter by urea binding [J].
Weber, G ;
DaPoian, AT ;
Silva, JL .
BIOPHYSICAL JOURNAL, 1996, 70 (01) :167-173