Distinct stability of recombinant L and H subunits of human ferritin: calorimetric and ANS binding studies.


Abstract

Thermodynamic and pH stability of recombinant human L- and H-ferritins were probed by differential scanning calorimetry and 8-anilino-1-naphthalenesulfonate (ANS) binding in the pH range 2-7. At pH 2.0-2.8 they were dissociated into subunit monomers and in this pH interval the H-subunit displayed a single calorimetrically-revealed domain with properties of a molten globule-like state: low enthalpy (6.3-8.0 J/g or 169-172 kJ/mol) and Tm of thermal unfolding (approximately 50 degrees C), a wide transition range (approximately 20 degrees C) and high ANS binding. In contrast, at pH 2 the L-ferritin subunit showed two calorimetric domains with Tm of 35 and 40 degrees C with similar unfolding enthalpies and with moderate extent of interactions, as indicated by the ratio of calorimetric enthalpy (293.9 kJ/mol) and van't Hoff enthalpy (174.2 kJ/mol) for the thermal transition. A pH increase from 2.0 to 2.8 determined the coupling of the two domains into a single cooperative folding unit and drastic increase of the transition temperature (from 37 to 80 degrees C). The contacts between the two domains in the L-subunit appeared to contribute to about 30% of the total stabilization free energy. The unfolding enthalpies, heat capacity changes and pronounced ANS binding of the L-subunit at pH 2.0-2.8 indicated that part of the structure lacked 'meltable' tertiary interactions. The results indicate that H- and L-subunits are stabilized by largely different intra-chain interactions with a critical contribution to L-subunit stability of embedded salt bridge(s) absent in the H-subunit. Study holds ProTherm entries: 3456, 3457, 3458, 3459, 3460, 3461, 3462 Extra Details: differential scanning calorimetry; ferritin subunits;,protein folding; protein stability

Submission Details

ID: atuxeD5Q4

Submitter: Connie Wang

Submission Date: April 24, 2018, 8:21 p.m.

Version: 1

Publication Details
Martsev SP;Vlasov AP;Arosio P,Protein Eng. (1998) Distinct stability of recombinant L and H subunits of human ferritin: calorimetric and ANS binding studies. PMID:9681870
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
3WNW 2013-12-17T00:00:00+0000 2.24 Structure of Mouse H-chain modified ferritin
5OBA 2017-06-26T00:00:00+0000 2.85 Structure of a modified mouse H-chain ferritin with a lanthanide binding motif
5OBB 2017-06-26T00:00:00+0000 2.65 Structure of a modified mouse H chain ferritin with a lanthanide binding motif in complex with Terbium
6S61 2019-07-02T00:00:00+0000 1.84 Apoferritin from mouse at 1.84 angstrom resolution
6SHT 2019-08-08T00:00:00+0000 2.73 Molecular structure of mouse apoferritin resolved at 2.7 Angstroms with the Glacios cryo-microscope
6V21 2019-11-21T00:00:00+0000 1.75 Mouse heavy chain apoferritin determined using single-particle cryo-EM at 200 keV
7A4M 2020-08-20T00:00:00+0000 1.22 Cryo-EM structure of mouse heavy-chain apoferritin at 1.22 A
7KOD 2020-11-08T00:00:00+0000 1.66 Cryo-EM structure of heavy chain mouse apoferritin
2FFX 2005-12-20T00:00:00+0000 1.9 Structure of Human Ferritin L. Chain
2FG4 2005-12-21T00:00:00+0000 2.1 Structure of Human Ferritin L Chain

Relevant UniProtKB Entries

Percent Identity Matching Chains Protein Accession Entry Name
100.0 Ferritin light chain P02792 FRIL_HUMAN
98.9 Ferritin light chain Q5R538 FRIL_PONAB
99.5 Ferritin heavy chain P02794 FRIH_HUMAN
98.9 Ferritin heavy chain Q5R8J7 FRIH_PONAB
95.6 Ferritin heavy chain Q9XT73 FRIH_TRIVU
95.6 Ferritin heavy chain Q95MP7 FRIH_CANLF
94.5 Ferritin heavy chain Q2MHN2 FRIH_FELCA
93.4 Ferritin heavy chain P29389 FRIH_CRIGR
94.4 Ferritin heavy chain P19132 FRIH_RAT
92.2 Ferritin heavy chain Q8MIP0 FRIH_HORSE
92.8 Ferritin heavy chain P09528 FRIH_MOUSE
90.6 Ferritin heavy chain O46414 FRIH_BOVIN
92.6 Ferritin heavy chain P08267 FRIH_CHICK
95.7 Ferritin heavy chain P25915 FRIH_RABIT
92.5 Ferritin heavy chain P18685 FRIH_SHEEP