Denaturant mediated unfolding of both native and molten globule states of maltose binding protein are accompanied by large deltaCp's.


Abstract

Maltose binding protein (MBP) is a large, monomeric two domain protein containing 370 amino acids. In the absence of denaturant at neutral pH, the protein is in the native state, while at pH 3.0 it forms a molten globule. The molten globule lacks a tertiary circular dichroism signal but has secondary structure similar to that of the native state. The molten globule binds 8-anilino-1-naphthalene sulfonate (ANS). The unfolding thermodynamics of MBP at both pHs were measured by carrying out a series of isothermal urea melts at temperatures ranging from 274-329 K. At 298 K, values of deltaGdegrees , deltaCp, and Cm were 3.1+/-0.2 kcal mol(-1), 5.9+/-0.8 kcal mol(-1) K(-1) (15.9 cal (mol-residue)(-1) K(-1)), and 0.8 M, respectively, at pH 3.0 and 14.5+/-0.4 kcal mol(-1), 8.3+/-0.7 kcal mol(-1) K(-1) (22.4 kcal (mol-residue)(-1) K(-1)), and 3.3 M, respectively, at pH 7.1. Guanidine hydrochloride denaturation at pH 7.1 gave values of deltaGdegrees and deltaCp similar to those obtained with urea. The m values for denaturation are strongly temperature dependent, in contrast to what has been previously observed for small globular proteins. The value of deltaCp per mol-residue for the molten globule is comparable to corresponding values of deltaCp for the unfolding of typical globular proteins and suggests that it is a highly ordered structure, unlike molten globules of many small proteins. The value of deltaCp per mol-residue for the unfolding of the native state is among the highest currently known for any protein. Study holds ProTherm entries: 6763, 6764, 6765, 6766, 6767, 6768, 6769, 6770, 6771, 6772, 6773, 6774, 6775, 6776, 6777, 6778, 6779, 6780, 6781, 6782, 6783, 6784, 6785, 6786, 6787, 6788, 6789, 6790, 6791, 6792 Extra Details: heat capacity; molten globule; protein stability

Submission Details

ID: wBr343gR3

Submitter: Connie Wang

Submission Date: April 24, 2018, 8:32 p.m.

Version: 1

Publication Details
Sheshadri S;Lingaraju GM;Varadarajan R,Protein Sci. (1999) Denaturant mediated unfolding of both native and molten globule states of maltose binding protein are accompanied by large deltaCp's. PMID:10452613
Additional Information

Number of data points 90
Proteins Maltose-binding periplasmic protein ; Maltose-binding periplasmic protein
Unique complexes 1
Assays/Quantities/Protocols Experimental Assay: Cm pH:3.0, ionic:: , temp:303 K ; Experimental Assay: m pH:3.0, ionic:: , temp:303 K ; Experimental Assay: dG_H2O pH:3.0, ionic:: , temp:303 K ; Experimental Assay: Cm pH:3.0, ionic:: , temp:300 K ; Experimental Assay: m pH:3.0, ionic:: , temp:300 K ; Experimental Assay: dG_H2O pH:3.0, ionic:: , temp:300 K ; Experimental Assay: Cm temp:299 K, pH:3.0, ionic:: ; Experimental Assay: m temp:299 K, pH:3.0, ionic:: ; Experimental Assay: dG_H2O temp:299 K, pH:3.0, ionic:: ; Experimental Assay: Cm pH:3.0, ionic:: , temp:296 K ; Experimental Assay: m pH:3.0, ionic:: , temp:296 K ; Experimental Assay: dG_H2O pH:3.0, ionic:: , temp:296 K ; Experimental Assay: Cm pH:3.0, temp:291 K, ionic:: ; Experimental Assay: m pH:3.0, temp:291 K, ionic:: ; Experimental Assay: dG_H2O pH:3.0, ionic:: , temp:291 K ; Experimental Assay: Cm temp:287 K, pH:3.0, ionic:: ; Experimental Assay: m temp:287 K, pH:3.0, ionic:: ; Experimental Assay: dG_H2O temp:287 K, pH:3.0, ionic:: ; Experimental Assay: Cm pH:3.0, ionic:: , temp:282 K ; Experimental Assay: m pH:3.0, ionic:: , temp:282 K ; Experimental Assay: dG_H2O pH:3.0, ionic:: , temp:282 K ; Experimental Assay: Cm temp:276 K, pH:3.0, ionic:: ; Experimental Assay: m temp:276 K, pH:3.0, ionic:: ; Experimental Assay: dG_H2O temp:276 K, pH:3.0, ionic:: ; Experimental Assay: Cm ionic:KCl: 150 mM, pH:7.1, temp:318 K ; Experimental Assay: m ionic:KCl: 150 mM, pH:7.1, temp:318 K ; Experimental Assay: dG_H2O ionic:KCl: 150 mM, pH:7.1, temp:318 K ; Experimental Assay: Cm ionic:KCl: 150 mM, pH:7.1, temp:313 K ; Experimental Assay: m ionic:KCl: 150 mM, pH:7.1, temp:313 K ; Experimental Assay: dG_H2O ionic:KCl: 150 mM, pH:7.1, temp:313 K ; Experimental Assay: Cm temp:309 K, pH:7.1, ionic:KCl: 150 mM ; Experimental Assay: m temp:309 K, pH:7.1, ionic:KCl: 150 mM ; Experimental Assay: dG_H2O temp:309 K, pH:7.1, ionic:KCl: 150 mM ; Experimental Assay: Cm ionic:KCl: 150 mM, temp:304 K, pH:7.1 ; Experimental Assay: m ionic:KCl: 150 mM, temp:304 K, pH:7.1 ; Experimental Assay: dG_H2O ionic:KCl: 150 mM, temp:304 K, pH:7.1 ; Experimental Assay: Cm temp:298 K, pH:7.1, ionic:KCl: 150 mM ; Experimental Assay: m temp:298 K, pH:7.1, ionic:KCl: 150 mM ; Experimental Assay: dG_H2O temp:298 K, pH:7.1, ionic:KCl: 150 mM ; Experimental Assay: Cm ionic:KCl: 150 mM, pH:7.1, temp:293 K ; Experimental Assay: m ionic:KCl: 150 mM, pH:7.1, temp:293 K ; Experimental Assay: dG_H2O ionic:KCl: 150 mM, pH:7.1, temp:293 K ; Experimental Assay: Cm ionic:KCl: 150 mM, pH:7.1, temp:284 K ; Experimental Assay: m ionic:KCl: 150 mM, pH:7.1, temp:284 K ; Experimental Assay: dG_H2O ionic:KCl: 150 mM, pH:7.1, temp:284 K ; Experimental Assay: Cm ionic:KCl: 150 mM, temp:274 K, pH:7.1 ; Experimental Assay: m ionic:KCl: 150 mM, temp:274 K, pH:7.1 ; Experimental Assay: dG_H2O ionic:KCl: 150 mM, temp:274 K, pH:7.1 ; Experimental Assay: Cm ionic:KCl: 150 mM, pH:7.1, temp:329 K ; Experimental Assay: m ionic:KCl: 150 mM, pH:7.1, temp:329 K ; Experimental Assay: dG_H2O ionic:KCl: 150 mM, pH:7.1, temp:329 K ; Experimental Assay: Cm ionic:KCl: 150 mM, temp:328 K, pH:7.1 ; Experimental Assay: m ionic:KCl: 150 mM, temp:328 K, pH:7.1 ; Experimental Assay: dG_H2O ionic:KCl: 150 mM, temp:328 K, pH:7.1 ; Experimental Assay: Cm ionic:KCl: 150 mM, temp:319 K, pH:7.1 ; Experimental Assay: m ionic:KCl: 150 mM, temp:319 K, pH:7.1 ; Experimental Assay: dG_H2O ionic:KCl: 150 mM, temp:319 K, pH:7.1 ; Experimental Assay: Cm ionic:KCl: 150 mM, pH:7.1, temp:313 K ; Experimental Assay: m ionic:KCl: 150 mM, pH:7.1, temp:313 K ; Experimental Assay: dG_H2O ionic:KCl: 150 mM, pH:7.1, temp:313 K ; Experimental Assay: Cm temp:312 K, pH:7.1, ionic:KCl: 150 mM ; Experimental Assay: m temp:312 K, pH:7.1, ionic:KCl: 150 mM ; Experimental Assay: dG_H2O temp:312 K, pH:7.1, ionic:KCl: 150 mM ; Experimental Assay: Cm ionic:KCl: 150 mM, pH:7.1, temp:310 K ; Experimental Assay: m ionic:KCl: 150 mM, pH:7.1, temp:310 K ; Experimental Assay: dG_H2O ionic:KCl: 150 mM, pH:7.1, temp:310 K ; Experimental Assay: Cm ionic:KCl: 150 mM, temp:307 K, pH:7.1 ; Experimental Assay: m ionic:KCl: 150 mM, temp:307 K, pH:7.1 ; Experimental Assay: dG_H2O ionic:KCl: 150 mM, temp:307 K, pH:7.1 ; Experimental Assay: Cm temp:306 K, ionic:KCl: 150 mM, pH:7.1 ; Experimental Assay: m temp:306 K, ionic:KCl: 150 mM, pH:7.1 ; Experimental Assay: dG_H2O temp:306 K, ionic:KCl: 150 mM, pH:7.1 ; Experimental Assay: Cm ionic:KCl: 150 mM, pH:7.1, temp:303 K ; Experimental Assay: m ionic:KCl: 150 mM, pH:7.1, temp:303 K ; Experimental Assay: dG_H2O ionic:KCl: 150 mM, pH:7.1, temp:303 K ; Experimental Assay: Cm ionic:KCl: 150 mM, temp:299 K, pH:7.1 ; Experimental Assay: m ionic:KCl: 150 mM, temp:299 K, pH:7.1 ; Experimental Assay: dG_H2O ionic:KCl: 150 mM, temp:299 K, pH:7.1 ; Experimental Assay: Cm ionic:KCl: 150 mM, pH:7.1, temp:293 K ; Experimental Assay: m ionic:KCl: 150 mM, pH:7.1, temp:293 K ; Experimental Assay: dG_H2O ionic:KCl: 150 mM, pH:7.1, temp:293 K ; Experimental Assay: Cm temp:287 K, ionic:KCl: 150 mM, pH:7.1 ; Experimental Assay: m temp:287 K, ionic:KCl: 150 mM, pH:7.1 ; Experimental Assay: dG_H2O temp:287 K, ionic:KCl: 150 mM, pH:7.1 ; Experimental Assay: Cm ionic:KCl: 150 mM, pH:7.1, temp:282 K ; Experimental Assay: m ionic:KCl: 150 mM, pH:7.1, temp:282 K ; Experimental Assay: dG_H2O ionic:KCl: 150 mM, pH:7.1, temp:282 K ; Experimental Assay: Cm ionic:KCl: 150 mM, temp:277 K, pH:7.1 ; Experimental Assay: m ionic:KCl: 150 mM, temp:277 K, pH:7.1 ; Experimental Assay: dG_H2O ionic:KCl: 150 mM, temp:277 K, pH:7.1
Libraries Mutations for sequence KIEEGKLVIWINGDKGYNGLAEVGKKFEKDTGIKVTVEHPDKLEEKFPQVAATGDGPDIIFWAHDRFGGYAQSGLLAEITPDKAFQDKLYPFTWDAVRYNGKLIAYPIAVEALSLIYNKDLLPNPPKTWEEIPALDKELKAKGKSALMFNLQEPYFTWPLIAADGGYAFKYENGKYDIKDVGVDNAGAKAGLTFLVDLIKNKHMNADTDYSIAEAAFNKGETAMTINGPWAWSNIDTSKVNYGVTVLPTFKGQPSKPFVGVLSAGINAASPNKELAKEFLENYLLTDEGLEAVNKDKPLGAVALKSYEEELAKDPRIAATMENAQKGEIMPNIPQMSAFWYAVRTAVINAASGRQTVDEALKDAQTRITK
Sequence Assay Result Units