Structural Characterization of Genomes by Large Scale Sequence-Structure Threading: Application of Reliability Analysis in Structural Genomics

Background: We establish that the occurrence of protein folds among genomes can be accuratelydescribed with a Weibull function. Systems which exhibit Weibull character can be interpretedwith reliability theory commonly used in engineering analysis. For instance, Weibull distributionsare widely used in reliability, maintainability and safety work to model time-to-failure of mechanicaldevices, mechanisms, building constructions and equipment.Results: We have found that the Weibull function describes protein fold distribution within andamong genomes more accurately than conventional power functions which have been used in anumber of structural genomic studies reported to date.It has also been found that the Weibull reliability parameter β for protein fold distributions variesbetween genomes and may reflect differences in rates of gene duplication in evolutionary historyof organisms.Conclusions: The results of this work demonstrate that reliability analysis can provide usefulinsights and testable predictions in the fields of comparative and structural genomics.