Role of the N-terminal helix I for dimerization and stability of the calcium-binding protein S100B.


Abstract

Human S100B(beta beta) is a small intracellular EF-hand calcium-binding protein that consists of two noncovalently associated 91-residue beta monomers. The three-dimensional structures of S100B reveal the dimer interface consists of four alpha-helices (I, I' and IV, IV') packed in an X-type bundle. In this study, guanidine hydrochloride denaturation and dynamic light scattering were used to assess the impact of single (L3A, L3S, M7A, I11A, F14A) and double (L3A/I11A and L3A/F14A) substitution mutations in helix I on the stability and dimerization propensity of S100B. The free energy of unfolding (Delta G(u)) of wild-type apo-S100B was determined to be 72.4 +/- 4.0 kJ mol(-1), consistent with it being the most stable calcium-binding protein to date. The order of stability of the mutants in their apo form is S100B > L3A > L3S > I11A > M7A approximately L3A/I11A > F14A > L3A/F14A. Further, there is a strong correlation between the stability and the cooperativity of unfolding. Each mutation proved to be more stable in its calcium form compared to its apo form. The calcium-bound L3S substitution proved to be significantly more stable than calcium-saturated S100B, whereas the L3A, I11A, and L3A/I11A mutants are only slightly more stable than the wild-type protein. The F14A and L3A/F14A mutants are significantly reduced in stability, even in the presence of calcium. Study holds ProTherm entries: 13045, 13046, 13047, 13048, 13049, 13050, 13051, 13052, 13053, 13054, 13055, 13056, 13057, 13058, 13059, 13060 Extra Details: apo form; 1mM DTT and 1mM EDTA were added in the experiment. EF-hand; free energy; cooperativity; calcium

Submission Details

ID: RgpQ7zPQ3

Submitter: Connie Wang

Submission Date: April 24, 2018, 8:44 p.m.

Version: 1

Publication Details
Ferguson PL;Shaw GS,Biochemistry (2002) Role of the N-terminal helix I for dimerization and stability of the calcium-binding protein S100B. PMID:11888280
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
1B4C 1998-12-17T00:00:00+0000 0 SOLUTION STRUCTURE OF RAT APO-S100B USING DIPOLAR COUPLINGS
1DT7 2000-01-11T00:00:00+0000 0 SOLUTION STRUCTURE OF THE C-TERMINAL NEGATIVE REGULATORY DOMAIN OF P53 IN A COMPLEX WITH CA2+-BOUND S100B(BB)
1MWN 2002-09-30T00:00:00+0000 0 Solution NMR structure of S100B bound to the high-affinity target peptide TRTK-12
1QLK 1997-09-26T00:00:00+0000 0 SOLUTION STRUCTURE OF CA(2+)-LOADED RAT S100B (BETABETA) NMR, 20 STRUCTURES
1SYM 1996-05-29T00:00:00+0000 0 3-D SOLUTION STRUCTURE OF REDUCED APO-S100B FROM RAT, NMR, 20 STRUCTURES
1XYD 2004-11-09T00:00:00+0000 0 NMR Solution Structure of Rat Zinc-Calcium-S100B, 20 Structures
2K7O 2008-08-17T00:00:00+0000 0 Ca2+-S100B, refined with RDCs
1MQ1 2002-09-13T00:00:00+0000 0 Ca2+-S100B-TRTK-12 complex
1UWO 1997-12-05T00:00:00+0000 0 CALCIUM FORM OF HUMAN S100B, NMR, 20 STRUCTURES
2H61 2006-05-30T00:00:00+0000 1.9 X-ray structure of human Ca2+-loaded S100B

Relevant UniProtKB Entries

Percent Identity Matching Chains Protein Accession Entry Name
96.7 Protein S100-B P02638 S100B_BOVIN
97.8 Protein S100-B P04631 S100B_RAT
98.9 Protein S100-B P50114 S100B_MOUSE
100.0 Protein S100-B Q6YNR6 S100B_RABIT
100.0 Protein S100-B P04271 S100B_HUMAN