Effects of the stabilization of the molten globule state on the folding mechanism of alpha-lactalbumin: a study of a chimera of bovine and human alpha-lactalbumin.


Abstract

The N-terminal half of the alpha-domain (residues 1 to 34) is more important for the stability of the acid-induced molten globule state of alpha-lactalbumin than the C-terminal half (residues 86 to 123). The refolding and unfolding kinetics of a chimera, in which the amino acid sequence of residues 1 to 34 was from human alpha-lactalbumin and the remainder of the sequence from bovine alpha-lactalbumin, were studied by stopped-flow tryptophan fluorescence spectroscopy. The chimeric protein refolded and unfolded substantially faster than bovine alpha-lactalbumin. The stability of the molten globule state formed by the chimera was greater than that of bovine alpha-lactalbumin, and the hydrophobic surface area buried inside of the molecule in the molten globule state was increased by the substitution of residues 1 to 34. Peptide fragments corresponding to the A- and B-helix of the chimera showed higher helix propensity than those of the bovine protein, indicating the contribution of local interactions to the high stability of the molten globule state of the chimera. Moreover, the substitution of residues 1-34 decreased the free energy level of the transition state and increased hydrophobic surface area buried inside of the molecule in the transition state. Our results indicate that local interactions as well as hydrophobic interactions formed in the molten globule state are important in guiding the subsequent structural formation of alpha-lactalbumin. Study holds ProTherm entries: 19613, 19614, 19615, 19616, 19617, 19618 Extra Details: Native to intermediate alpha-lactalbumin; molten globule; protein folding; stability; local interaction

Submission Details

ID: Si2Lqe2L

Submitter: Connie Wang

Submission Date: April 24, 2018, 8:51 p.m.

Version: 1

Publication Details
Mizuguchi M;Matsuura A;Nabeshima Y;Masaki K;Watanabe M;Aizawa T;Demura M;Nitta K;Mori Y;Shinoda H;Kawano K,Proteins (2005) Effects of the stabilization of the molten globule state on the folding mechanism of alpha-lactalbumin: a study of a chimera of bovine and human alpha-lactalbumin. PMID:16121399
Additional Information

Structure view and single mutant data analysis

Study data

No weblogo for data of varying length.
Colors: D E R H K S T N Q A V I L M F Y W C G P
 

Data Distribution

Studies with similar sequences (approximate matches)

Correlation with other assays (exact sequence matches)


Relevant PDB Entries

Structure ID Release Date Resolution Structure Title
3B0K 2012-06-13 1.6 Crystal structure of alpha-lactalbumin
1FKQ 2001-02-14 1.8 RECOMBINANT GOAT ALPHA-LACTALBUMIN T29V
6IP9 2019-02-20 1.85 Crystal Structure of Lanthanum ion (La3+) bound bovine alpha-lactalbumin
1HMK 1999-11-26 2.0 RECOMBINANT GOAT ALPHA-LACTALBUMIN
1FKV 2001-02-14 2.0 RECOMBINANT GOAT ALPHA-LACTALBUMIN T29I
1F6S 2000-12-13 2.2 CRYSTAL STRUCTURE OF BOVINE ALPHA-LACTALBUMIN
1F6R 2000-12-13 2.2 CRYSTAL STRUCTURE OF APO-BOVINE ALPHA-LACTALBUMIN
1HFY 1997-07-07 2.3 ALPHA-LACTALBUMIN
1HFZ 1997-07-29 2.3 ALPHA-LACTALBUMIN
2G4N 2007-02-20 2.3 Anomalous substructure of alpha-lactalbumin

Relevant UniProtKB Entries

Percent Identity Matching Chains Protein Accession Entry Name
95.1 Alpha-lactalbumin P00712 LALBA_CAPHI
97.2 Alpha-lactalbumin P09462 LALBA_SHEEP
98.6 Alpha-lactalbumin Q9TSN6 LALBA_BUBBU
99.3 Alpha-lactalbumin Q9TSR4 LALBA_BOSMU
100.0 Alpha-lactalbumin P00711 LALBA_BOVIN