Pair bonding

Productive only when wedded to another molecule, the protein relies upon this structure to play the role of matchmaker, embedding an advertisement for a soul mate in the loops, bulges, and trenches created on its outer surface by the folds:

"Are You My Better Half?" -- SFP (single folded protein) with secure position in healthy cell seeks compatible molecule with interest in chemical engineering, architecture, or communication for exclusive short-term relationship. Please reply with details of your chemical structure.

The molecule with the most compatible profile wins the date and enters into a marriage of convenience, arranged by evolution to accomplish a specialized task. Paired with a matching substrate, an enzyme speeds up a vital chemical reaction. A rotor protein and a flagellar protein conspire to move a bacterium. [13]

Niefhoff, Debra. The Language of Life: How Cells Communicate in Health and Disease. Joseph Henry Press, 2005. ISBN: 0309089891.