The opening appears to be timed to occur well after proton transfer from the Schiff base (a process that may be mediated by a chain of water molecules not unlike those observed in this study) linked to the protonation state of Asp96 and exists only long enough to fulfill the function of reprotonating Asp96.
Core streptavidin and the corresponding single-chain dimer mediated a biotin binding of about 3.9 and 1.5 ng biotin/μg bead protein, respectively.
Surprisingly, we observe that the nor PKS can mediate an additional chain elongation to yield the higher homolog homoneoaureothin.
After all clinical follow-up had ended, cervical cytology samples were tested for the presence of HPV DNA using a general primer (GP5+/GP6+) mediated polymerase chain reaction (PCR), and further PCR tests were done with type-specific primers on samples that were HPV-positive after ethidium bromide staining.
Gene disruptions and C-terminal tagging were performed using a technique mediated by polymerase chain reaction (PCR) (Longtine et al. 1998).
We find that NF structure is sensitive to changes in brush thickness mediated by chain charge, consistent with the experimental observation that sidearm phosphorylation regulates interfilament spacing.
It has been suggested that PPII helices could be stabilized by water mediated main chain hydrogen bonds (in the absence of main chain-main chain H-bonds), as they also tend to have a regular pattern of hydrogen bonds with water [30].
What makes the code seem arbitrary is the fact that the mapping between base triplets and amino acids is mediated by a causal chain with a number of intervening links (especially involving "transfer RNA" molecules, and enzymes that bind amino acids to these intervening molecules).
The specific biological signal mediated by a polyubiquitin chain is determined, in part, by the chain topology, which is assigned by the Ub lysine residue used for chain extension.
In contrast, the coordination of the Ca+2 in site I (EF-hand motif), is largely mediated by main chain carbonyl of Glu67 and the side chains of Asp61, Asn63, Asp65 and Glu72.
