1MKG

DISULFIDE DEFICIENT MUTANT OF VASCULAR ENDOTHELIAL GROWTH FACTOR A (C57A and C102A)

Summary for 1MKG

• Entry DOI: 10.2210/pdb1mkg/pdb
• Related: 1MJV 1MKK 2VPF
• Descriptor: Vascular Endothelial Growth Factor A (2 entities in total)
• Functional Keywords: cystine-knot growth factor, hormone-growth factor complex, hormone/growth factor
• Biological source: Homo sapiens (human)
• Cellular location: Secreted : P15692
• Total number of polymer chains: 4
• Total formula weight: 44783.86

Authors

Muller, Y.A.,Heiring, C.,Misselwitz, R.,Welfle, K.,Welfle, H. (deposition date: 2002-08-29, release date: 2002-12-11, Last modification date: 2024-10-09)

Primary citation

Muller, Y.A.,Heiring, C.,Misselwitz, R.,Welfle, K.,Welfle, H.
The cystine knot promotes folding and not thermodynamic stability in vascular endothelial growth factor
J.Biol.Chem., 277:43410-43416, 2002

PubMed Abstract: Cystine knots consist of three intertwined disulfide bridges and are considered major determinants of protein stability in proteins in which they occur. We questioned this function and observed that removal of individual disulfide bridges in human vascular endothelial growth factor (VEGF) does not reduce its thermodynamic stability but reduces its unexpected high thermal stability of 108 degrees C by up to 40 degrees C. In wild-type VEGF (deltaG(u,25)(0) = 5.1 kcal.mol(-1)), the knot is responsible for a large entropic stabilization of TdeltaS(u,25)(0) = -39.3 kcal mol(-1), which is compensated for by a deltaH(u,25)(0) of -34.2 kcal mol(-1). In the disulfide-deficient mutants, this entropic stabilization disappears, but instead of a decrease, we observe an increase in the thermodynamic stability by about 2 kcal.mol(-1). A detailed crystallographic analysis of the mutant structures suggests a role of the cystine knot motif in protein folding rather than in the stabilization of the folded state. When assuming that the sequential order of the disulfide bridge formation is conserved between VEGF and glycoprotein alpha-subunit, the crystal structure of the mutant C61A-C104A, which deviates by a root mean square deviation of more than 2.2 A from wild-type VEGF, identifies a true folding intermediate of VEGF.

PubMed: 12207021
DOI: 10.1074/jbc.M206438200

Experimental method

X-RAY DIFFRACTION (2.5 Å)