The genome sequence of the thermoacidophilic scavenger Thermoplasma acidophilum

Thermoplasma acidophilum is a thermoacidophilic archaeon that thrives at 59 degrees C and pH 2, which was isolated from self-heating coal refuse piles and solfatara fields(1,2). Species of the genus Thermoplasma do not posses s a rigid cell wall, but are only delimited by a plasma membrane. Many macr omolecular assemblies from Thermoplasma, primarily proteases and chaperones , have been pivotal in elucidating the structure and function of their more complex eukaryotic homologues(3,4). Our interest in protein folding and de gradation led us to seek a more complete representation of the proteins inv olved 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 sequen cing reactions by using a new strategy. The 1,509 open reading frames ident ify Thermoplasma as a typical euryarchaeon with a substantial complement of bacteria-related genes; however, evidence indicates that there has been mu ch 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 pa thway and various transport proteins, resemble Sulfolobus proteins most clo sely.