Biomaterial Database

Importance of the C-terminal loop L137-S141 for the folding and folding stability of staphylococcal nuclease. 2010

Min Wang, and Yingang Feng, and Hongwei Yao, and Jinfeng Wang

National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, 15 Datun Road, Beijing 100101, China.

The role of the C-terminal loop L137-S141 in the folding and folding stability of staphylococcal nuclease (SNase) was investigated by deletion mutation. The C-terminal truncated SNase fragments, SNase137, SNase139, SNase140, and SNase141 containing residues 1-137, 1-139, 1-140, and 1-141, respectively, were adopted in this study. Folding states of these four SNase fragments were analyzed by circular dichroism and fluorescence measurements. The solution structure of SNase140 was determined and compared to those of SNase141 and native SNase using the heteronuclear NMR method. The results showed that folding of the four SNase fragments is correlated with the folding of helix alpha3. With the chain length extending from L137 and I139 to S141, folding of the fragments progressively approached to the tertiary folding of native SNase, and the folding stability was enhanced. These observations revealed that the C-terminal loop L137-S141 has profound effect not only on the folding of helix alpha3 but also on the stabilizing folding of both the alpha- and beta-subdomains of SNase. Analysis indicates that stabilizing folding of the SNase and SNase fragments depends to a large extent on the hydrophobic packing interactions in both the C-terminal local structural region surrounding W140 including the loop L137-S141 and the N-terminal local structural region of the "beta-barrel" hydrophobic core.

UI	MeSH Term	Description	Entries
D008836	Micrococcal Nuclease	An enzyme that catalyzes the endonucleolytic cleavage to 3'-phosphomononucleotide and 3'-phospholigonucleotide end-products. It can cause hydrolysis of double- or single-stranded DNA or RNA. (From Enzyme Nomenclature, 1992) EC 3.1.31.1.	Staphylococcal Nuclease,TNase,Thermonuclease,Thermostable Nuclease,Nuclease, Micrococcal,Nuclease, Staphylococcal,Nuclease, Thermostable
D008958	Models, Molecular	Models used experimentally or theoretically to study molecular shape, electronic properties, or interactions; includes analogous molecules, computer-generated graphics, and mechanical structures.	Molecular Models,Model, Molecular,Molecular Model
D010446	Peptide Fragments	Partial proteins formed by partial hydrolysis of complete proteins or generated through PROTEIN ENGINEERING techniques.	Peptide Fragment,Fragment, Peptide,Fragments, Peptide
D011489	Protein Denaturation	Disruption of the non-covalent bonds and/or disulfide bonds responsible for maintaining the three-dimensional shape and activity of the native protein.	Denaturation, Protein,Denaturations, Protein,Protein Denaturations
D004789	Enzyme Activation	Conversion of an inactive form of an enzyme to one possessing metabolic activity. It includes 1, activation by ions (activators); 2, activation by cofactors (coenzymes); and 3, conversion of an enzyme precursor (proenzyme or zymogen) to an active enzyme.	Activation, Enzyme,Activations, Enzyme,Enzyme Activations
D014508	Urea	A compound formed in the liver from ammonia produced by the deamination of amino acids. It is the principal end product of protein catabolism and constitutes about one half of the total urinary solids.	Basodexan,Carbamide,Carmol
D017433	Protein Structure, Secondary	The level of protein structure in which regular hydrogen-bond interactions within contiguous stretches of polypeptide chain give rise to ALPHA-HELICES; BETA-STRANDS (which align to form BETA-SHEETS), or other types of coils. This is the first folding level of protein conformation.	Secondary Protein Structure,Protein Structures, Secondary,Secondary Protein Structures,Structure, Secondary Protein,Structures, Secondary Protein
D017434	Protein Structure, Tertiary	The level of protein structure in which combinations of secondary protein structures (ALPHA HELICES; BETA SHEETS; loop regions, and AMINO ACID MOTIFS) pack together to form folded shapes. Disulfide bridges between cysteines in two different parts of the polypeptide chain along with other interactions between the chains play a role in the formation and stabilization of tertiary structure.	Tertiary Protein Structure,Protein Structures, Tertiary,Tertiary Protein Structures
D017510	Protein Folding	Processes involved in the formation of TERTIARY PROTEIN STRUCTURE.	Protein Folding, Globular,Folding, Globular Protein,Folding, Protein,Foldings, Globular Protein,Foldings, Protein,Globular Protein Folding,Globular Protein Foldings,Protein Foldings,Protein Foldings, Globular
D055550	Protein Stability	The ability of a protein to retain its structural conformation or its activity when subjected to physical or chemical manipulations.	Protein Stabilities,Stabilities, Protein,Stability, Protein