Premium
Capture of monomeric refolding intermediate of human muscle creatine kinase
Author(s) -
Li Sen,
Bai JiHong,
Park YongDoo,
Zhou HaiMeng
Publication year - 2006
Publication title -
protein science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.353
H-Index - 175
eISSN - 1469-896X
pISSN - 0961-8368
DOI - 10.1110/ps.051738406
Subject(s) - monomer , groel , chemistry , chaperonin , molten globule , protein folding , biochemistry , biophysics , guanidinium chloride , folding (dsp implementation) , creatine kinase , guanidine , enzyme , protein aggregation , biology , organic chemistry , escherichia coli , electrical engineering , gene , engineering , polymer
Human muscle creatine kinase (CK) is an enzyme that plays an important physiological role in the energy metabolism of humans. It also serves as a typical model for studying refolding of proteins. A study of the refolding and reactivation process of guanidine chloride–denatured human muscle CK is described in the present article. The results show that the refolding process can be divided into fast and slow folding phases and that an aggregation process competes with the proper refolding process at high enzyme concentration and high temperature. An intermediate in the early stage of refolding was captured by specific protein molecules: the molecular chaperonin GroEL and α s ‐casein. This intermediate was found to be a monomer, which resembles the “molten globule” state in the CK folding pathway. To our knowledge, this is the first monomeric intermediate captured during refolding of CK. We propose that aggregation is caused by interaction between such monomeric intermediates. Binding of GroEL with this intermediate prevents formation of aggregates by decreasing the concentration of free monomeric intermediates, whereas binding of α s ‐casein with this intermediate induces more aggregation.