Investigation of the structural stability of the human acidic fibroblast growth factor by hydrogen-deuterium exchange.
The conformational stability of the human acidic fibroblast growth factor (hFGF-1) is investigated using amide proton exchange and temperature-dependent chemical shifts, monitored by two-dimensional NMR spectroscopy. The change in free energy of unfolding (DeltaG(u)) of hFGF-1 is estimated to be 5.00 +/- 0.09 kcal.mol(-)(1). Amide proton-exchange rates of 74 residues (in hFGF-1) have been unambiguously measured, and the exchange process occurs predominately according to the conditions of the EX2 limit. The exchange rates of the fast-exchanging amide protons exposed to the solvent have been measured using the clean SEA-HSQC technique. The amide proton protection factor and temperature coefficient estimates show reasonably good correlation. Residues in beta-strands II and VI appear to constitute the stability core of the protein. Among the 12 beta-strands constituting the beta-barrel architecture of hFGF-1, beta-strand XI, located in the heparin binding domain, exhibits the lowest average protection factor value. Amide protons involved in the putative folding nucleation site in hFGF-1, identified by quench-flow NMR studies, do not represent the slow-exchanging core. Residues in portions of hFGF-1 experiencing high conformational flexibility mostly correspond to those involved in receptor recognition and binding.
Chi
Ya-Hui
YH
Department of Chemistry, National Tsing Hua University, Hsinchu 30013, Taiwan.
Kumar
Thallampuranam Krishnaswamy S
TK
Kathir
Karuppanan Muthusamy
KM
Lin
Dong-Hai
DH
Zhu
Guang
G
Chiu
Ing-Ming
IM
Yu
Chin
C
D000577:Amides / Q000737:chemistry; D003903:Deuterium / Q000737:chemistry*; D016220:Fibroblast Growth Factor 1 / Q000737:chemistry*; D006801:Humans; D006860:Hydrogen Bonding; D007700:Kinetics; D019906:Nuclear Magnetic Resonance, Biomolecular; D011487:Protein Conformation; D011489:Protein Denaturation; D017510:Protein Folding; D017433:Protein Structure, Secondary; D011522:Protons; D020794:Receptor Protein-Tyrosine Kinases / Q000737:chemistry; D051496:Receptor, Fibroblast Growth Factor, Type 1; D017468:Receptors, Fibroblast Growth Factor / Q000737:chemistry; D013050:Spectrometry, Fluorescence; D013696:Temperature; D013816:Thermodynamics; D014508:Urea / Q000737:chemistry
D000577:Amides; D011522:Protons; D017468:Receptors, Fibroblast Growth Factor; D016220:Fibroblast Growth Factor 1; D014508:Urea; D003903:Deuterium; C496348:FGFR1 protein, human; D020794:Receptor Protein-Tyrosine Kinases; D051496:Receptor, Fibroblast Growth Factor, Type 1