The genome sequence of the thermoacidophilic scavenger Thermoplasma acidophilum

Thermoplasma acidophilum is a thermoacidophilic archaeon that thrives at 59 °C and pH 2, which was isolated from self-heating coal refuse piles and solfatara fields1,2. Species of the genus Thermoplasma do not possess a rigid cell wall, but are only delimited by a plasma membrane. Many macromolecular assemblies from Thermoplasma , primarily proteases and chaperones, have been pivotal in elucidating the structure and function of their more complex eukaryotic homologues3,4. Our interest in protein folding and degradation led us to seek a more complete representation of the proteins involved in these pathways by determining the genome sequence of the organism. Here we have sequenced the 1,564,905-base-pair genome in just 7,855 sequencing reactions by using a new strategy. The 1,509 open reading frames identify Thermoplasma as a typical euryarchaeon with a substantial complement of bacteria-related genes; however, evidence indicates that there has been much lateral gene transfer between Thermoplasma and Sulfolobus solfataricus, a phylogenetically distant crenarchaeon inhabiting the same environment. At least 252 open reading frames, including a complete protein degradation pathway and various transport proteins, resemble Sulfolobus proteins most closely.