| Structural highlights
Function
[TRFL_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 PubMed
Human lactoferrin is an iron-binding protein with a bilobal structure. Each lobe contains a high-affinity binding site for a single Fe(3+) ion and an associated CO(3)(2-) ion. Although iron binds very tightly, it can be released at low pH, with an accompanying conformational change in which the two domains move apart. The Arg121Asp (R121D) mutant of the N-lobe half-molecule of human lactoferrin was constructed in order to test whether the Asp121 side chain could substitute for the CO(3)(2-) ion at the iron-binding site. The R121D mutant protein was crystallized in its apo form as it lost iron during crystallization. The crystals were also merohedrally twinned, with a twin fraction close to 0.5. Starting from the initial molecular-replacement solution [Breyer et al. (1999), Acta Cryst. D55, 129-138], the structure has been refined at 3.0 A resolution to an R factor of 13.9% (R(free) of 19.9%). Despite the moderate resolution, the high solvent content and non-crystallographic symmetry contributed to electron-density maps of excellent quality. Weakened iron binding by the R121D mutant is explained by occlusion of the anion-binding site by the Asp side chain. The opening of the two domains in the apoR121D structure (a rotation of 54 degrees ) closely matches that of the N-lobe in full-length lactoferrin, showing that the extent of the conformational change depends on properties inherent to the N-lobe. Differences in the C-terminal portion of the N-lobe (residues 321-332) for apoR121D relative to the closed wild-type iron-bound structure point to the importance of this region in stabilizing the open form.
Structure of a domain-opened mutant (R121D) of the human lactoferrin N-lobe refined from a merohedrally twinned crystal form.,Jameson GB, Anderson BF, Breyer WA, Day CL, Tweedie JW, Baker EN Acta Crystallogr D Biol Crystallogr. 2002 Jun;58(Pt 6 Pt 2):955-62. Epub, 2002 May 29. PMID:12037297[11]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
References
- ↑ Hendrixson DR, Qiu J, Shewry SC, Fink DL, Petty S, Baker EN, Plaut AG, St Geme JW 3rd. Human milk lactoferrin is a serine protease that cleaves Haemophilus surface proteins at arginine-rich sites. Mol Microbiol. 2003 Feb;47(3):607-17. PMID:12535064
- ↑ Mariller C, Hardiville S, Hoedt E, Huvent I, Pina-Canseco S, Pierce A. Delta-lactoferrin, an intracellular lactoferrin isoform that acts as a transcription factor. Biochem Cell Biol. 2012 Jun;90(3):307-19. doi: 10.1139/o11-070. Epub 2012 Feb 9. PMID:22320386 doi:http://dx.doi.org/10.1139/o11-070
- ↑ Hendrixson DR, Qiu J, Shewry SC, Fink DL, Petty S, Baker EN, Plaut AG, St Geme JW 3rd. Human milk lactoferrin is a serine protease that cleaves Haemophilus surface proteins at arginine-rich sites. Mol Microbiol. 2003 Feb;47(3):607-17. PMID:12535064
- ↑ Mariller C, Hardiville S, Hoedt E, Huvent I, Pina-Canseco S, Pierce A. Delta-lactoferrin, an intracellular lactoferrin isoform that acts as a transcription factor. Biochem Cell Biol. 2012 Jun;90(3):307-19. doi: 10.1139/o11-070. Epub 2012 Feb 9. PMID:22320386 doi:http://dx.doi.org/10.1139/o11-070
- ↑ Hendrixson DR, Qiu J, Shewry SC, Fink DL, Petty S, Baker EN, Plaut AG, St Geme JW 3rd. Human milk lactoferrin is a serine protease that cleaves Haemophilus surface proteins at arginine-rich sites. Mol Microbiol. 2003 Feb;47(3):607-17. PMID:12535064
- ↑ Mariller C, Hardiville S, Hoedt E, Huvent I, Pina-Canseco S, Pierce A. Delta-lactoferrin, an intracellular lactoferrin isoform that acts as a transcription factor. Biochem Cell Biol. 2012 Jun;90(3):307-19. doi: 10.1139/o11-070. Epub 2012 Feb 9. PMID:22320386 doi:http://dx.doi.org/10.1139/o11-070
- ↑ Hendrixson DR, Qiu J, Shewry SC, Fink DL, Petty S, Baker EN, Plaut AG, St Geme JW 3rd. Human milk lactoferrin is a serine protease that cleaves Haemophilus surface proteins at arginine-rich sites. Mol Microbiol. 2003 Feb;47(3):607-17. PMID:12535064
- ↑ Mariller C, Hardiville S, Hoedt E, Huvent I, Pina-Canseco S, Pierce A. Delta-lactoferrin, an intracellular lactoferrin isoform that acts as a transcription factor. Biochem Cell Biol. 2012 Jun;90(3):307-19. doi: 10.1139/o11-070. Epub 2012 Feb 9. PMID:22320386 doi:http://dx.doi.org/10.1139/o11-070
- ↑ Hendrixson DR, Qiu J, Shewry SC, Fink DL, Petty S, Baker EN, Plaut AG, St Geme JW 3rd. Human milk lactoferrin is a serine protease that cleaves Haemophilus surface proteins at arginine-rich sites. Mol Microbiol. 2003 Feb;47(3):607-17. PMID:12535064
- ↑ Mariller C, Hardiville S, Hoedt E, Huvent I, Pina-Canseco S, Pierce A. Delta-lactoferrin, an intracellular lactoferrin isoform that acts as a transcription factor. Biochem Cell Biol. 2012 Jun;90(3):307-19. doi: 10.1139/o11-070. Epub 2012 Feb 9. PMID:22320386 doi:http://dx.doi.org/10.1139/o11-070
- ↑ Jameson GB, Anderson BF, Breyer WA, Day CL, Tweedie JW, Baker EN. Structure of a domain-opened mutant (R121D) of the human lactoferrin N-lobe refined from a merohedrally twinned crystal form. Acta Crystallogr D Biol Crystallogr. 2002 Jun;58(Pt 6 Pt 2):955-62. Epub, 2002 May 29. PMID:12037297
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