Detecting changes in the functional constraints of paralogous genes.
We describe a new procedure to determine whether regional alterations in the evolutionary constraints imposed on paralogous proteins have occurred. We used as models the A and B (alternatively called alpha and beta) subunits of V/F/A-ATPases, originated by a gene duplication more than 3 billion years ago. Changes associated to three major splits (eubacteria versus Archaea-eukaryotes; Archaea versus eukaryotes; and among free-living bacteria and symbiotic mitochondria) were studied. Only in the first case, when we compared eubacterial or mitochondrial F-ATPases versus eukaryotic vacuolar V-ATPases or archaeal A-ATPases, constraint changes were observed. Modifications in the degree of regional constraining were not detected for the other two types of comparisons (V-ATPases versus A-ATPases and within F-ATPases, respectively). When the rates of evolution of the two subunits were compared, it was found that F-ATPases regulatory subunits evolved faster than catalytic subunits, but the opposite was true for A- and V-ATPases. Our results suggest that, even for universal and essential proteins, selective constraints may be occasionally altered. On the other hand, in some cases no changes were detected after periods of more than 2.2 billion years.
Marín
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I
Instituto Cavanilles de Biodiversidad y Biología Evolutiva, Universidad de Valencia, Dr. Moliner, 50, Burjassot 46100, Valencia, Spain. ignacio.marin@uv.es
Fares
M A
MA
González-Candelas
F
F
Barrio
E
E
Moya
A
A
D000251:Adenosine Triphosphatases / Q000737:chemistry / Q000235:genetics*; D000595:Amino Acid Sequence; D019843:Archaeal Proteins / Q000737:chemistry / Q000235:genetics*; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics*; D019143:Evolution, Molecular; D008928:Mitochondria / Q000502:physiology; D008969:Molecular Sequence Data; D011487:Protein Conformation; D017434:Protein Structure, Tertiary; D021122:Protein Subunits; D006180:Proton-Translocating ATPases / Q000737:chemistry / Q000235:genetics; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA / Q000379:methods*; D025262:Vacuolar Proton-Translocating ATPases
D019843:Archaeal Proteins; D001426:Bacterial Proteins; D021122:Protein Subunits; D000251:Adenosine Triphosphatases; D025262:Vacuolar Proton-Translocating ATPases; D006180:Proton-Translocating ATPases