Conservation of Protein Structure over Four Billion Years

• Published in: Structure (London) 2013-09, Vol.21 (9), p.1690-1697
• Main Authors: Ingles-Prieto, Alvaro, Ibarra-Molero, Beatriz, Delgado-Delgado, Asuncion, Perez-Jimenez, Raul, Fernandez, Julio M., Gaucher, Eric A., Sanchez-Ruiz, Jose M., Gavira, Jose A.
• Format: Article
• Language: English
• Subjects: Amino Acid Sequence; Archaeal Proteins - chemistry; Conservation; Conserved Sequence; Crystal structure; Crystallography, X-Ray; Dating; Escherichia coli Proteins - chemistry; Evolution; Evolution, Molecular; Humans; Hydrogen Bonding; Models, Molecular; Phylogeny; Planetary evolution; Protein Structure, Secondary; Protein Structure, Tertiary; Proteins; Structural Homology, Protein; Thioredoxins - chemistry; Time; X-rays
• ISSN: 0969-2126; 1878-4186
• DOI: 10.1016/j.str.2013.06.020

Little is known about the evolution of protein structures and the degree of protein structure conservation over planetary time scales. Here, we report the X-ray crystal structures of seven laboratory resurrections of Precambrian thioredoxins dating up to approximately four billion years ago. Despite considerable sequence differences compared with extant enzymes, the ancestral proteins display the canonical thioredoxin fold, whereas only small structural changes have occurred over four billion years. This remarkable degree of structure conservation since a time near the last common ancestor of life supports a punctuated-equilibrium model of structure evolution in which the generation of new folds occurs over comparatively short periods and is followed by long periods of structural stasis. [Display omitted] •3D structure determination reliably extended to approximately four billion years ago•Ancestral and derived structural features in extant proteins readily identified•Remarkable degree of structure conservation back to a time close to the origin of life•Illustration of a powerful approach to explore the evolution of protein structures Ingles-Prieto et al. report structures for seven resurrected Precambrian thioredoxins dating back to about four billion years ago. Despite considerable sequence differences compared with extant enzymes, the ancestral proteins display the canonical fold and reveal a remarkable degree of structure conservation.