In
molecular biology
Molecular biology is the branch of biology that seeks to understand the molecular basis of biological activity in and between cells, including biomolecular synthesis, modification, mechanisms, and interactions. The study of chemical and physi ...
, holdases are a particular kind of
molecular chaperones
In molecular biology, molecular chaperones are proteins that assist the conformational folding or unfolding of large proteins or macromolecular protein complexes. There are a number of classes of molecular chaperones, all of which function to assi ...
that assist the non-covalent folding of proteins in an ATP-independent manner. Examples of holdases are
DnaJ
In molecular biology, chaperone DnaJ, also known as Hsp40 (heat shock protein 40 kD), is a molecular chaperone protein. It is expressed in a wide variety of organisms from bacteria to humans.
Function
Molecular chaperones are a diverse family o ...
and
Hsp33
Hsp33 protein is a molecular chaperone, distinguished from all other known chaperones by its mode of functional regulation. Its activity is redox regulated. Hsp33 is a cytoplasmically localized protein with highly reactive cysteines that respond ...
.
Holdases bind to protein folding intermediates to prevent their aggregation but without directly refolding them. They stand in opposition to
foldase In molecular biology, foldases are a particular kind of molecular chaperones that assist the non-covalent folding of proteins in an ATP-dependent manner. Examples of foldase systems are the GroEL/ GroES and the DnaK/ DnaJ/GrpE system.
References
...
s, which are chaperones that use ATP to fold proteins.
See also
*
Foldase In molecular biology, foldases are a particular kind of molecular chaperones that assist the non-covalent folding of proteins in an ATP-dependent manner. Examples of foldase systems are the GroEL/ GroES and the DnaK/ DnaJ/GrpE system.
References
...
*
Chaperonin
HSP60, also known as chaperonins (Cpn), is a family of heat shock proteins originally sorted by their 60kDa molecular mass. They prevent misfolding of proteins during stressful situations such as high heat, by assisting protein folding. HSP60 bel ...
*
Co-chaperone
Co-chaperones are proteins that assist chaperone (protein), chaperones in protein folding and other functions. Co-chaperones are the non-client binding molecules that assist in protein folding mediated by Hsp70 and Hsp90. They are particularly esse ...
References
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Molecular chaperones
Protein biosynthesis