LOX, an extracellular matrix-remodeling enzyme, is required for the oxidative deamination of lysine residues in collagen and elastin molecules that is required for fiber cross-linking; hence, LOX controls both the structure and the tensile strength of ECM, and thus acts to preserve tissue integrity [10].
P4HAs are required for collagen cross-linking and the expression of P4HA1 and P4HA2 is directly regulated by HIF-1.
For example, the absence of Crh1p and Crh2p, which are required for the cross-linking of chitin to glucan, induces hypersensitivity to CR and CW [ 14].
Given that B is essential for cell wall elongation, where it is required for the cross-linking of the pectic polysaccharide rhamnogalacturonan II [ 24], the constitutive expression of MtNIP3 in the roots and leaves is not surprising as MtNIP3 may always be needed to give B access to sink tissues for normal plant growth.
As described above, Phr1 is required for the proper cross-linking of β-1,3 and β-1,6-glucans.
Amidation of lipid II is required for efficient peptidoglycan cross-linking in some Gram positive bacteria, including S. pneumoniae, and non-amidated glutamate-containing peptides were indeed found to be scarce in S. pneumoniae [ 60].
Consistently with other studies in eukaryotes, the E3 ubiquitin ligase Rhp18 was found to be required for wild-type resistance to interstrand cross-links (supplementary Fig. 1 and [8,40 42].
In order to achieve the desired spatial geometry required for cross-linking, the concentration of IgE antibodies attached to the mast cell membranes must be of sufficient number.
Dissection of the signaling pathway led to a model where H3S10ph recruits the deacetylase Hst2p, and this interaction was required for H2A H4 cross-link formation and hence chromatin compaction.
Peletskaya et al. [27], [28] showed that a template extension of 5 to 7 nucleotides was required for maximal efficiency of cross-linking between sulfhydryl groups tethered at specific positions in the template strand and cysteine residues introduced into the fingers subdomain of RT.
