1mkk
From Proteopedia
Disulfide deficient mutant of vascular endothelial growth factor A (C61A and C104A)
Structural highlights
Disease[VEGFA_HUMAN] Defects in VEGFA are a cause of susceptibility to microvascular complications of diabetes type 1 (MVCD1) [MIM:603933]. These are pathological conditions that develop in numerous tissues and organs as a consequence of diabetes mellitus. They include diabetic retinopathy, diabetic nephropathy leading to end-stage renal disease, and diabetic neuropathy. Diabetic retinopathy remains the major cause of new-onset blindness among diabetic adults. It is characterized by vascular permeability and increased tissue ischemia and angiogenesis. Function[VEGFA_HUMAN] Growth factor active in angiogenesis, vasculogenesis and endothelial cell growth. Induces endothelial cell proliferation, promotes cell migration, inhibits apoptosis and induces permeabilization of blood vessels. Binds to the FLT1/VEGFR1 and KDR/VEGFR2 receptors, heparan sulfate and heparin. NRP1/Neuropilin-1 binds isoforms VEGF-165 and VEGF-145. Isoform VEGF165B binds to KDR but does not activate downstream signaling pathways, does not activate angiogenesis and inhibits tumor growth.[1] [2] [3] Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedCystine 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. The cystine knot promotes folding and not thermodynamic stability in vascular endothelial growth factor.,Muller YA, Heiring C, Misselwitz R, Welfle K, Welfle H J Biol Chem. 2002 Nov 8;277(45):43410-6. Epub 2002 Aug 30. PMID:12207021[4] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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