1nkx
CRYSTAL STRUCTURE OF A PROTEOLYTICALLY GENERATED FUNCTIONAL MONOFERRIC C-LOBE OF BOVINE LACTOFERRIN AT 1.9A RESOLUTION
Structural highlights
FunctionTRFL_BOVIN 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. The most effective inhibitory activity was seen against E.coli and P.aeruginosa.[3] [4] Lactoferricin B is an antimicrobial peptide. Inhibits the growth of Gram-negative and Gram-positive bacteria.[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] 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 PubMedThis is the first crystal structure of a proteolytically generated functional C-lobe of lactoferrin. The purified samples of iron-saturated C-lobe were crystallized in 0.1 M Mes buffer (pH 6.5) containing 25% (v/v) polyethyleneglycol monomethyl ether 550 M and 0.1 M zinc sulphate heptahydrate. The X-ray intensity data were collected with 300 mm imaging plate scanner mounted on a rotating anode generator. The structure was determined by the molecular replacement method using the coordinates of the C-terminal half of bovine lactoferrin as a search model and refined to an R-factor of 0.193 for all data to 1.9A resolution. The final model comprises 2593 protein atoms (residues 342-676 and 681-685), 124 carbohydrate atoms (from ten monosaccharide units, in three glycan chains), one Fe(3+), one CO(3)(2-), two Zn(2+) and 230 water molecules. The overall folding of the C-lobe is essentially the same as that of C-terminal half of bovine lactoferrin but differs slightly in conformations of some of the loops and reveals a number of new interactions. There are 20 Cys residues in the C-lobe forming ten disulphide links. Out of these, one involving Cys481-Cys675 provides an inter-domain link at 2.01A while another Cys405-Cys684 is formed between the main C-lobe 342-676 and the hydrolyzed pentapeptide 681-685 fragment. Six inter-domain hydrogen bonds have been observed in the structure whereas only four were reported in the structure of intact lactoferrin, although domain orientations have been found similar in the two structures. The good quality of electron density has also revealed all the ten oligosaccharide units in the structure. The observation of two metal ions at sites other than the iron-binding cleft is another novel feature of the present structure. These zinc ions stabilize the crystal packing. This structure is also notable for extensive inter-molecular hydrogen bonding in the crystals. Therefore, the present structure appears to be one of the best packed crystal structures among the proteins of the transferrin superfamily. Crystal structure of a proteolytically generated functional monoferric C-lobe of bovine lactoferrin at 1.9A resolution.,Sharma S, Jasti J, Kumar J, Mohanty AK, Singh TP J Mol Biol. 2003 Aug 8;331(2):485-96. PMID:12888354[9] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
| ||||||||||||||||||||
