1DC9

PROPERTIES AND CRYSTAL STRUCTURE OF A BETA-BARREL FOLDING MUTANT, V60N INTESTINAL FATTY ACID BINDING PROTEIN (IFABP)

Summary for 1DC9

• Entry DOI: 10.2210/pdb1dc9/pdb
• Related: 1ICM 1ICN 1IFB 1IFC 2IFB
• Descriptor: INTESTINAL FATTY ACID BINDING PROTEIN (2 entities in total)
• Functional Keywords: fatty acid binding protein, intracellular lipid binding protein, mutant, beta- barrel, lipid binding protein
• Biological source: Rattus norvegicus (Norway rat)
• Cellular location: Cytoplasm: P02693
• Total number of polymer chains: 1
• Total formula weight: 15029.99

Authors

Ropson, I.J.,Yowler, B.C.,Dalessio, P.M.,Banaszak, L.,Thompson, J. (deposition date: 1999-11-04, release date: 2000-03-20, Last modification date: 2024-02-07)

Primary citation

Ropson, I.J.,Yowler, B.C.,Dalessio, P.M.,Banaszak, L.,Thompson, J.
Properties and crystal structure of a beta-barrel folding mutant.
Biophys.J., 78:1551-1560, 2000

PubMed Abstract: A mutant of a beta-barrel protein, rat intestinal fatty acid binding protein, was predicted to be more stable than the wild-type protein due to a novel hydrogen bond. Equilibrium denaturation studies indicated the opposite: the V60N mutant protein was less stable. The folding transitions followed by CD and fluorescence were reversible and two-state for both mutant and wild-type protein. However, the rates of denaturation and renaturation of V60N were faster. During unfolding, the initial rate was associated with 75-80% of the fluorescence and all of the CD amplitude change. A subsequent rate accounted for the remaining fluorescence change for both proteins; thus the intermediate state lacked secondary structure. During folding, one rate was detected by both fluorescence and CD after an initial burst phase for both wild-type and mutant. An additional slower folding rate was detected by fluorescence for the mutant protein. The structure of the V60N mutant has been obtained and is nearly identical to prior crystal structures of IFABP. Analysis of mean differences in hydrogen bond and van der Waals interactions did not readily account for the stability loss due to the mutation. However, significant average differences of the solvent accessible surface and crystallographic displacement factors suggest entropic destabilization.

PubMed: 10692339

Experimental method

X-RAY DIFFRACTION (2.1 Å)