Domain structure and interactions of the type I and type II modules in the gelatin-binding region of fibronectin. All six modules are independently folded.


Abstract

The gelatin-binding region of fibronectin is isolated easily as a stable and functional 42 kDa fragment containing four type I "finger" modules and two type II "kringle-like" modules arranged in the order I6-II1-II2-I7-I8-I9. This fragment exhibits a single reversible melting transition near 64 degrees C in TBS buffer (0.02 M-Tris buffer containing 0.15 M-NaCl, pH 7.4). The transition is characterized by a calorimetric to van't Hoff enthalpy ratio of 1.6, suggesting a complex domain structure. A 30 kDa fragment with the same NH2 terminus (I6-II1-II2-I7) melts reversibly near 65 degrees C with delta Hcal/delta HvH = 1.3, also consistent with the presence of more than one domain. To elucidate further the domain structure, three non-overlapping subfragments were prepared and characterized with respect to their unfolding induced by heat and guanidinium chloride. The three subfragments, each containing two modules, are designated from amino or carboxyl-terminal location as 13 kDa (I6-II1) 16 kDa (II2-I7) and 21 kDa (I8-I9) according to their apparent Mr in SDS/polyacrylamide gel electrophoresis. All three subfragments exhibited reversible transitions in TBS buffer, behaving in the calorimeter as single co-operative units with delta Hcal/delta HvH close to unity. However, the specific enthalpies and changes in heat capacity associated with the melting of all fragments and subfragments in TBS buffer were low compared to those of most compact globular proteins, suggesting that not all modules are represented. When titrated with guanidinium chloride at 25 degrees C, all fragments exhibited monophasic reversible unfolding transitions detected by changes in fluorescence. Heating in the presence of 6 M-guanidinium chloride revealed three additional transitions not seen in the absence of denaturants. These transitions have been assigned to three of the four type I finger modules (I6, I7 and I9), one of which (I6) was isolated and shown to retain a compact structure as stable as that observed for this module within the parent fragments. Two other modules (II2 and I7) are destabilized when separated from their neighbors. Thus, despite their small size (50 to 60 amino acid residues), all six of the modules in the gelatin-binding region of fibronectin form independently folded domains, three of which (I6, I7 and I9) are unusually stable. Evidence is provided that four of the six modules interact with each other in the parent fragment. This interaction may explain previously noted disruptions in the otherwise uniform strand-like images seen in electron micrographs of fibronectin. Study holds ProTherm entries: 7124, 7125, 7126, 7127, 7128, 7129, 7130 Extra Details: gelatin-binding region; "kringle-like" modules; subfragments;,co-operative units

Submission Details

ID: RQo9nLvU3

Submitter: Connie Wang

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

Version: 1

Publication Details
Litvinovich SV;Strickland DK;Medved LV;Ingham KC,J. Mol. Biol. (1991) Domain structure and interactions of the type I and type II modules in the gelatin-binding region of fibronectin. All six modules are independently folded. PMID:1994038
Additional Information

Study Summary

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
1E88 2000-09-18T00:00:00+0000 0 Solution structure of 6F11F22F2, a compact three-module fragment of the gelatin-binding domain of human fibronectin
1E8B 2000-09-18T00:00:00+0000 0 Solution structure of 6F11F22F2, a compact three-module fragment of the gelatin-binding domain of human fibronectin
1FBR 1995-08-08T00:00:00+0000 0 FOURTH AND FIFTH FIBRONECTIN TYPE I MODULE PAIR
1FNA 1994-01-11T00:00:00+0000 1.8 CRYSTAL STRUCTURE OF THE TENTH TYPE III CELL ADHESION MODULE OF HUMAN FIBRONECTIN
1FNF 1995-09-30T00:00:00+0000 2.0 FRAGMENT OF HUMAN FIBRONECTIN ENCOMPASSING TYPE-III REPEATS 7 THROUGH 10
1FNH 1999-01-28T00:00:00+0000 2.8 CRYSTAL STRUCTURE OF HEPARIN AND INTEGRIN BINDING SEGMENT OF HUMAN FIBRONECTIN
1J8K 2001-05-22T00:00:00+0000 0 NMR STRUCTURE OF THE FIBRONECTIN EDA DOMAIN, NMR, 20 STRUCTURES
1O9A 2002-12-11T00:00:00+0000 0 Solution structure of the complex of 1F12F1 from fibronectin with B3 from FnBB from S. dysgalactiae
1OWW 2003-03-31T00:00:00+0000 0 Solution structure of the first type III module of human fibronectin determined by 1H, 15N NMR spectroscopy
1Q38 2003-07-28T00:00:00+0000 0 Anastellin

Relevant UniProtKB Entries

Percent Identity Matching Chains Protein Accession Entry Name
96.8 Fibronectin P07589 FINC_BOVIN
100.0 Fibronectin P02751 FINC_HUMAN
90.9 Fibronectin Q91400 FINC_NOTVI
92.1 Fibronectin Q28377 FINC_HORSE
94.0 Fibronectin Q28275 FINC_CANLF