Abstract
Advances in proteogenomic technologies have revealed hundreds to
thousands of translated small open reading frames (sORFs) that encode
microproteins in genomes across evolutionary space. While many
microproteins have now been shown to play critical roles in biology and
human disease, a majority of recently identified microproteins have
little or no experimental evidence regarding their functionality.
Computational tools have some limitations for analysis of short, poorly
conserved microprotein sequences, so additional tools are needed to
determine the role of each member of this recently discovered
polypeptide class. A currently underexplored avenue in the study of
microproteins is structure prediction and determination, which delivers
a depth of functional information. In this review, we provide a brief
overview of microprotein discovery methods, then examine examples of
microprotein structures (and, conversely, intrinsic disorder) that have
been experimentally determined using crystallography, cryo-electron
microscopy, and NMR, which provide insight into their molecular
functions and mechanisms. Additionally, we discuss examples of predicted
microprotein structures that have provided insight or context regarding
their function. Analysis of microprotein structure at the angstrom
level, and confirmation of predicted structures, therefore, has
potential to identify translated microproteins that are of biological
importance and to provide molecular mechanism for their in vivo roles.