STABILITY OF PHAGE-T4 LYSOZOMES .2. UNFOLDING WITH GUANIDINIUM CHLORIDE

被引:22
作者
ELWELL, ML [1 ]
SCHELLMAN, JA [1 ]
机构
[1] UNIV OREGON,INST MOLEC BIOL,EUGENE,OR 97403
基金
美国国家科学基金会; 美国国家卫生研究院;
关键词
(Phage T4); Guanidine denaturation; Lysozyme; Mutant protein; Stability; Temperature sensitivity;
D O I
10.1016/0005-2795(79)90145-4
中图分类号
Q5 [生物化学]; Q7 [分子生物学];
学科分类号
071010 ; 081704 ;
摘要
The denaturation by guanidinium chloride of three phage lysozymes (wild type and two mutants) was investigated. The study of solvent denaturation permitted the investigation of the relative stabilities of the proteins at neutral pH, in contrast to thermal denaturation studies reported earlier which could only be performed in acid pH. The results were interpreted assuming that the free energy of solution of proteins is a linear function of denaturant concentration. Using standard thermodynamic formulas this permits the calculation of the stabilities of the three proteins in the absence of guanidinium chloride. The single point mutation Trp 138 → Tyr leads to relatively large changes in stability and the interaction of the protein with guanidinium chloride. The changes associated with the subsequent double mutation, Trp 126 → Tyr, Trp 158 → Tyr, are much smaller indicating a relatively smooth adjustment of the protein structure to the changed side chains. Models of the structural effects of point mutations are discussed. It is found that the mutation at position 138 does not fit a model in which the effect of a substitution is to introduce an energetic strain in the structure. It does fit a model in which there is a partial unravelling of the structure as a result of the mutation. However, there are no changes in the backbone circular dichroism spectra associated with the mutation. The two observations are not necessarily in conflict. Further physical studies are required for the resolution of the problem. © 1979.
引用
收藏
页码:327 / 338
页数:12
相关论文
共 21 条
[1]  
ALEXANDER SS, 1971, BIOCHEMISTRY-US, V10, P2738, DOI 10.1021/bi00790a013
[2]   THERMODYNAMICS OF DENATURATION OF LYSOZYME BY GUANIDINE HYDROCHLORIDE .2. DEPENDENCE ON DENATURANT CONCENTRATION AT 25 DEGREES [J].
AUNE, KC ;
TANFORD, C .
BIOCHEMISTRY, 1969, 8 (11) :4586-&
[3]  
CASSASA EF, 1964, ADV PROTEIN CHEM, V19, P287
[4]   PHAGE-T4 LYSOZYME - PHYSICAL-PROPERTIES AND REVERSIBLE UNFOLDING [J].
ELWELL, M ;
SCHELLMAN, J .
BIOCHIMICA ET BIOPHYSICA ACTA, 1975, 386 (01) :309-323
[5]   STABILITY OF PHAGE-T4 LYSOZYMES .1. NATIVE PROPERTIES AND THERMAL-STABILITY OF WILD-TYPE AND 2 MUTANT LYSOZYMES [J].
ELWELL, ML ;
SCHELLMAN, JA .
BIOCHIMICA ET BIOPHYSICA ACTA, 1977, 494 (02) :367-383
[6]  
GREENE RF, 1974, J BIOL CHEM, V249, P5388
[7]   STRUCTURAL STUDIES OF RIBONUCLEASE .5. REVERSIBLE CHANGE OF CONFIGURATION [J].
HERMANS, J ;
SCHERAGA, HA .
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, 1961, 83 (15) :3283-&
[8]  
KIELLEY WW, 1960, BIOCHIM BIOPHYS ACTA, V41, P401
[9]   GUANIDINE-HYDROCHLORIDE AND ACID DENATURATION OF HORSE, COW, AND CANDIDA-KRUSEI CYTOCHROMES-C [J].
KNAPP, JA ;
PACE, CN .
BIOCHEMISTRY, 1974, 13 (06) :1289-1294
[10]  
MATTHEWS BW, 1979, P NATL ACAD SCI US, V74, P4178