Crystal aggregation is promoted by viscous binding, implying that crystal-foreign compounds with multiple binding sites, such as abnormally self-aggregating Tamm-Horsfall glycoprotein or other macromolecules, attach to crystal surfaces and act as a kind of glue [ 37].
It is also apparent that THP inhibits crystal aggregation by steric hindrance rather than by binding to the crystal surfaces [ 22]; binding might therefore not be a prerequisite for inhibitory potency after all.
The retained amorphous organic material seen in the affected teeth may be a result of increased protein binding to the altered crystal surfaces and subsequent hindrance of the normal proteolytic breakdown of the enamel matrix.
Proteins bind to BCP crystals, including OCP, and to MSU crystal surfaces [ 34, 48, 49] and can modulate cell function in vivo and in vitro.
Among them, apolipoprotein (apo) B and apo E inhibit crystal-induced neutrophil stimulation by binding to the surface of crystals [ 19, 20].
Bisphosphonates inhibit calcification by binding to the surface of solid calcium phosphate crystals and acting as crystal poisons affecting both crystal growth and dissolution [ 47].
However, an unglycosylated Ala-Hyp-Ala repeat peptide did show significant TH and ice crystal re-shaping activity suggesting that it was capable of binding to the surface of ice.
A recently reported crystal structure of the Rad50 SMC head dimer, in complex with DNA, shows DNA binding to a surface loop rich in lysines, equivalent to the Smc3/Psm3 surface loop from which K105 and K106 emanate (Gligoris et al., 2014, Rojowska et al., 2014).
Antibodies isolated from rabbits injected with other types of crystals did not have the same effect on MSU nucleation and the authors suggested that this indicated high specificity between the antibody binding sites and the crystal surface, and the uric acid binding antibodies were acting as nucleating templates for MSU crystallization [ 47].
Computational modeling indicates that Nα-methylation leads to significant decrease in binding of the l-cystine diamides to l-cystine crystal surface.
