Macromolecular Mimicry of Nucleic Acid and Protein

Abstract

Although proteins and nucleic acids consist of different chemical components, proteins can mimic structures and possibly also functions of nucleic acids. Recently, structural mimicry was observed between two elongation factors in bacterial protein biosynthesis leading to the introduction of the concept of macromolecular mimicry. Macromolecular mimicry has further been proposed among initiation and release factors, thereby adding a new element to the description of protein synthesis in bacteria. Such mimicry has also been observed in other biological processes such as autoimmunity, DNA repair, and gene regulation, at both transcriptional and translational levels.

Macromolecular mimicry

“…The concept of ‘molecular mimicry’ is not new, and in the literature covers diverse fields such as the recognition of cell surfaces by viruses and other parasites, the binding of agonists and antagonists to receptors, and not least the cross‐reactions in autoimmune responses (for reviews, see Hall, 1994; Davies, 1997). However, the definition of ‘macromolecular mimicry’ used here is much narrower than that of ‘molecular mimicry’ and even narrower than that used in a recent review (Pedersen et al ., 1999). It only includes examples of mimicry for which there is either solid structural or reasonably solid biochemical evidence for a similarity in shape between proteins and nucleic acids.…”

Peptides as DNA mimics: cross-reactivity and mimicry in systemic autoimmune diseases

“…Molecular mimicry between DNA (or RNA) and protein, as well as mimicry between sugar and proteins [47], may result from other mechanisms. Despite the fact that nucleic acids (or carbohydrates) and proteins are chemically very different and are not expected to form the same shapes or to present the same chemical moieties on their surface, they might present identical or overlapping topological surfaces, which can be recognized by the same antibodies [8,22,48]. Autoantibodies are often polyreactive in nature; whether this property is associated with particular pathogenic functions is still unclear.…”