1vfe
HUMAN LACTOFERRIN, N-TERMINAL LOBE MUTANT WITH ARG 121 REPLACED BY SER (R121S)HUMAN LACTOFERRIN, N-TERMINAL LOBE MUTANT WITH ARG 121 REPLACED BY SER (R121S)
Structural highlights
FunctionTRFL_HUMAN Transferrins are iron binding transport proteins which can bind two Fe(3+) ions in association with the binding of an anion, usually bicarbonate.[1] [2] Lactotransferrin has antimicrobial activity which depends on the extracellular cation concentration.[3] [4] Lactoferroxins A, B and C have opioid antagonist activity. Lactoferroxin A shows preference for mu-receptors, while lactoferroxin B and C have somewhat higher degrees of preference for kappa-receptors than for mu-receptors.[5] [6] The lactotransferrin transferrin-like domain 1 functions as a serine protease of the peptidase S60 family that cuts arginine rich regions. This function contributes to the antimicrobial activity.[7] [8] Isoform DeltaLf: transcription factor with antiproliferative properties and inducing cell cycle arrest. Binds to DeltaLf response element found in the SKP1, BAX, DCPS, and SELH promoters.[9] [10] 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 PubMedA conserved arginine residue helps to form the synergistic anion binding site in transferrins. To probe the importance of this residue for anion binding and iron binding, Arg 121 has been mutated to Ser and Glu in N-terminal half-molecule of human lactoferrin. The two mutants, R121S and R121E, have been expressed, purified, and crystallized. Their three-dimensional structures have been determined by X-ray diffraction at 2.3 and 2.5 A resolution, respectively. The structures were determined by molecular replacement and were refined by restrained least squares methods to final R values of 0.185 and 0.204. Both mutants still bind iron but with decreased stability. The crystal structures show that destabilization of iron binding probably results from disruption of the anion binding site; mutation of Arg 121 removes one wall of the anion binding pocket and causes the synergistic carbonate ion to be displaced 0.5 A from its position in the wild-type protein. In the process it becomes partially detached from the helix N-terminus that forms the rest of the anion binding site. Mutation of arginine 121 in lactoferrin destabilizes iron binding by disruption of anion binding: crystal structures of R121S and R121E mutants.,Faber HR, Baker CJ, Day CL, Tweedie JW, Baker EN Biochemistry. 1996 Nov 19;35(46):14473-9. PMID:8931543[11] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
|
|