Tryptophan-19 of beta-lactoglobulin, the only residue completely conserved in the lipocalin superfamily, is not essential for binding retinol, but relevant to stabilizing bound retinol and maintaining its structure.


Abstract

Residue 19 of tryptophan in bovine beta-lactoglobulin (beta-LG) is the only invariant residue throughout the lipocalin superfamily having two characteristic features: binding ability for small hydrophobic molecules and the unique beta-barrel three-dimensional structure. In this study, we investigated whether this strictly conserved Trp-19 of beta-LG would be indispensable for its structure and function such as maintaining the molecular structure and biological activity of beta-LG. Spectroscopic and enzymatic oxidation experiments on retinol bound to W19Y, in which Tyr was substituted for Trp-19, showed that Trp-19 was not critical for this binding, but was important for stably maintaining the environment surrounding retinol and the bound retinol. An using four anti-beta-LG monoclonal antibodies as probes, revealed a structural change in region 20-29, but not in the reverse region of Trp-19. A guanidine hydrochloride-induced unfolding study showed that the conformational stability of W19Y was greatly reduced by 6.9 kcal/mol compared to that of wild-type beta-LG. These facts indicated that Trp-19 is one of the important residues in correctly maintaining the local structure of beta-LG and stably retaining its overall structure, thereby conserving the bound retinol molecule. Study holds ProTherm entries: 7256, 7257 Extra Details: NaN3(0.02%) was added in the experiment

Submission Details

ID: AMnKvqrq3

Submitter: Connie Wang

Submission Date: April 24, 2018, 8:33 p.m.

Version: 1

Publication Details
Katakura Y;Totsuka M;Ametani A;Kaminogawa S,Biochim. Biophys. Acta (1994) Tryptophan-19 of beta-lactoglobulin, the only residue completely conserved in the lipocalin superfamily, is not essential for binding retinol, but relevant to stabilizing bound retinol and maintaining its structure. PMID:8043610
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
4CK4 2013-12-27T00:00:00+0000 1.12 Ovine beta-Lactoglobulin at Atomic Resolution
4NLI 2013-11-14T00:00:00+0000 1.9 Crystal structure of sheep beta-lactoglobulin (space group P3121)
4NLJ 2013-11-14T00:00:00+0000 1.4 Crystal structure of sheep beta-lactoglobulin (space group P1)
6T44 2019-10-12T00:00:00+0000 2.0 Ovine lactoglobulin complex with decanol
4Y0S 2015-02-06T00:00:00+0000 1.9 Goat beta-lactoglobulin complex with pramocaine (GLG-PRM)
7LWC 2021-02-28T00:00:00+0000 3.0 Goat beta-lactoglobulin mutant Q59A
4OMW 2014-01-27T00:00:00+0000 2.3 Crystal structure of goat beta-lactoglobulin (orthorhombic form)
4OMX 2014-01-27T00:00:00+0000 2.3 Crystal structure of goat beta-lactoglobulin (trigonal form)
4TLJ 2014-05-30T00:00:00+0000 1.17 Ultra-high resolution crystal structure of caprine Beta-lactoglobulin
2Q2M 2007-05-29T00:00:00+0000 2.1 Beta-lactoglobulin (native)

Relevant UniProtKB Entries

Percent Identity Matching Chains Protein Accession Entry Name
95.7 Beta-lactoglobulin P67975 LACB_OVIMU
95.7 Beta-lactoglobulin P67976 LACB_SHEEP
96.3 Beta-lactoglobulin P02756 LACB_CAPHI
98.8 Beta-lactoglobulin P02755 LACB_BUBBU
100.0 Beta-lactoglobulin P02754 LACB_BOVIN