Computational validation of residue conservation
Details of the CENP-HK binding interface at the C-terminal was revealed in the crystal structure of the fungal HIK complex (5Z08). The side chain of ILE-205, ILE-211 and LEU-219 from th CENP-H were shown to insert into the hydrophobic pocket of th CENP-K which is surrounded by several residues including, LEU-177, TRP-179, PHE-180, HIS-184, ILE-270 and PHE-300. On the CENP-HI interface, th CENP-H uses its contacting helix (HH2) in interacting with thect CENP-INT HEAT repeat. A salt bridge was reported to be formed between the ARG-220 of th CENP-H and the GLU-86 of ct CENP-INT, while the LEU-224 of was reported to insert into the ct CENP-INThydrophobic pocket (surrounded by LEU-89, VAL-126 and VAL-130) [14]. The alignment of amino acid sequences from different orthologs of CENP-H (T. terrestris, G. gallus, O. aries, R. norvegicus, M. musculus and H. sapiens ) revealed a high degree of conservation in favour of the CENP-K and -I-binding residues of the protein, which in human correspond to LEU-219, VAL-225, LEU-233, LYS-234 and LEU-238 [14]. Using ConSurf, we validated the degree of conservation of the reported residues in the hs CENP-H model. The output depicted that all the five reported residues (LEU-219, VAL-225, LEU-233, LYS-234 and LEU-238) are conserved with varying degrees of conservation (Figure 4).