@article {4617,
	title = {Cavitands are effective templates for inducing stability and nativelike structure in de Novo four-helix bundles},
	journal = {Journal of the American Chemical Society},
	volume = {121},
	number = {39},
	year = {1999},
	note = {ISI Document Delivery No.: 243QXTimes Cited: 40Cited Reference Count: 92},
	month = {Oct},
	pages = {8983-8994},
	type = {Article},
	abstract = {We have designed, synthesized and characterized eight cavitand-based de novo four-helix bundles, where each helix contains the basis sequence EELLKKLEELLKKG. We find that each de novo protein is highly helical and extremely stable to the chemical denaturant guanidine hydrochloride (GuHCl). We studied the effect of the cavitand-peptide linker on the stability of each de novo protein. Flexible linkers render the helical structures more susceptible to denaturation by GuHCl. Linker structure and length also dictate monomer/dimer equilibria of the proteins. Proteins containing 0-3 Cry units possess varying degrees of nativelike structure. In contrast, proteins containing two or four methylene Linkers are more characteristic of molten globules. These differences can be attributed to the additional hydrogen bonding capabilities of the glycine linker variants and to the distance between the cavitand template and the helical bundle. The cavitand pendent group was also changed in one de novo protein from a methyl group to a propyl-phosphate moiety. This alteration does not affect the stability or packing within the helical bundle; however, it does affect the monomer/dimer equilibrium.},
	keywords = {4-HELIX BUNDLE, ASSEMBLED, conformational, DESIGNED PROTEIN, HOST GUEST COMPLEXATION, HYDROGEN-EXCHANGE, MOLTEN GLOBULE, NONPOLAR AMINO-ACIDS, rational design, STABILITY, SYNTHETIC PROTEINS, ULTRAVIOLET CIRCULAR-DICHROISM},
	isbn = {0002-7863},
	url = {<Go to ISI>://000083009700003},
	author = {Mezo, A. R. and Sherman, J. C.}
}
@article {4314,
	title = {Equilibrium unfolding of proteins monitored by electrospray ionization mass spectrometry: Distinguishing two-state from multi-state transitions},
	journal = {Rapid Communications in Mass Spectrometry},
	volume = {12},
	number = {8},
	year = {1998},
	note = {ISI Document Delivery No.: ZJ143Times Cited: 79Cited Reference Count: 59},
	pages = {435-442},
	type = {Article},
	abstract = {The acetic acid-induced unfolding of cytochrome c (cyt c) and apomyoglobin (aMb) are studied under equilibrium conditions by electrospray ionization (ESI) mass spectrometry (MS), The folding states of the proteins in solution are monitored by the charge state distributions that they produce during ESI, A tightly folded protein shows lower charge states than the same protein in an unfolded conformation. The ESI-MS data presented in this study show that during the denaturation of cyt c, only two distinct charge state distributions are observed. These can be attributed to the native and to the acid-unfolded conformation, respectively. In the transition region where the folded and the unfolded conformation are both present in solution, these two distributions are observed simultaneously, thus giving rise to a bimodal ESI mass spectrum. These data reflect a highly cooperative (two state) folding behavior. In contrast, the acid-induced unfolding of aMb is accompanied by gradual shifts in the maxima of the observed charge state distribution. This indicates a non cooperative unfolding behavior involving multiple protein conformations. The observations made here suggest that ESI-MS might be a general method for assessing the cooperativity of protein unfolding transitions. This study also addresses the issue of {\textquoteright}secondary{\textquoteright} solvent effects for ESI-MS studies on the acid-induced unfolding of proteins. These effects influence the ESI charge state distribution without being related to conformational changes of the protein in solution and could potentially complicate the interpretation of ESI mass spectra, Data obtained for bovine pancreatic trypsin inhibitor and ubiquitin indicate that secondary solvent effects influence the observed charge state distributions only to a very minor extent between pH 8.5 and 2.5. (C) 1998 John Wiley \& Sons, Ltd.},
	keywords = {CONFORMATIONAL-CHANGES, CYTOCHROME-C, FERRICYTOCHROME-C, FOLDING, HYDROGEN-DEUTERIUM EXCHANGE, INTERMEDIATE, MOLECULAR-BASIS, MOLTEN GLOBULE, NMR-SPECTROSCOPY, POSITIVE-ION, STRUCTURAL CHARACTERIZATION},
	isbn = {0951-4198},
	url = {<Go to ISI>://000073183800005},
	author = {Konermann, L. and Douglas, D. J.}
}
