Protein structure of MK. (a) MK protein structure is shown. MK consists of two domains with similar size connected by an interdomain (white box). Numbers indicate amino acid position within the protein. The heparin-binding sites consisting of basic amino acids are located in the C-terminal domain (green boxes) [20]. (b) Tertiary structure of the C-terminal domain of MK protein “taken from the protein data bank PDB via http://www.rcsb.org/pdb/explore.do?structureId=1MKC.” The C-terminal domain contains three β-strands (yellow structure). Heparin binding clusters consisting of basic amino acids (cluster 1: K79, R81, K102; cluster 2: K86, K87, R89 in human MK) are displayed as green dots. C62, C72, C94, and C104 represent highly conserved cysteine residues forming disulfide bonds (black lines) [20].
