Solution structure and backbone dynamics of human epidermal-type fatty acid-binding protein (E-FABP).
Human epidermal-type fatty acid-binding protein (E-FABP) belongs to a family of intracellular 14-15 kDa lipid-binding proteins, whose functions have been associated with fatty acid signalling, cell growth, regulation and differentiation. As a contribution to understanding the structure-function relationship, we report in the present study features of its solution structure and backbone dynamics determined by NMR spectroscopy. Applying multi-dimensional high-resolution NMR techniques on unlabelled and 15N-enriched recombinant human E-FABP, the 1H and 15N resonance assignments were completed. On the basis of 2008 distance restraints, the three-dimensional solution structure of human E-FABP was subsequently obtained (backbone atom root-mean-square deviation of 0.92+/-0.11 A; where 1 A=0.1 nm), consisting mainly of 10 anti-parallel beta-strands that form a beta-barrel structure. 15N relaxation experiments (T1, T2 and heteronuclear nuclear Overhauser effects) at 500, 600 and 800 MHz provided information on the internal dynamics of the protein backbone. Nearly all non-terminal backbone amide groups showed order parameters S(2)>0.8, with an average value of 0.88+/-0.04, suggesting a uniformly low backbone mobility in the nanosecond-to-picosecond time range. Moreover, hydrogen/deuterium exchange experiments indicated a direct correlation between the stability of the hydrogen-bonding network in the beta-sheet structure and the conformational exchange in the millisecond-to-microsecond time range. The features of E-FABP backbone dynamics elaborated in the present study differ markedly from those of the phylogenetically closely related heart-type FABP and the more distantly related ileal lipid-binding protein, implying a strong interdependence with the overall protein stability and possibly also with the ligand-binding affinity for members of the lipid-binding protein family.
Gutiérrez-González
Luis H
LH
Institut für Biophysikalische Chemie, Johann Wolfgang Goethe-Universität Frankfurt, Marie-Curie-Strasse 9, D-60439 Frankfurt am Main, Germany.
Ludwig
Christian
C
Hohoff
Carsten
C
Rademacher
Martin
M
Hanhoff
Thorsten
T
Rüterjans
Heinz
H
Spener
Friedrich
F
Lücke
Christian
C
D000595:Amino Acid Sequence; D002352:Carrier Proteins / Q000737:chemistry* / Q000378:metabolism; D000071438:Fatty Acid-Binding Protein 7; D050556:Fatty Acid-Binding Proteins; D005227:Fatty Acids / Q000378:metabolism; D006801:Humans; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009363:Neoplasm Proteins; D011487:Protein Conformation; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D011994:Recombinant Proteins / Q000737:chemistry / Q000378:metabolism; D012996:Solutions; D025521:Tumor Suppressor Proteins
D002352:Carrier Proteins; C493412:FABP5 protein, human; C107608:FABP7 protein, human; D000071438:Fatty Acid-Binding Protein 7; D050556:Fatty Acid-Binding Proteins; D005227:Fatty Acids; D009363:Neoplasm Proteins; D011994:Recombinant Proteins; D012996:Solutions; D025521:Tumor Suppressor Proteins