The complete genome sequence of Staphylothermus marinus reveals differences in sulfur metabolism among heterotrophic Crenarchaeota.
BACKGROUND
Staphylothermus marinus is an anaerobic, sulfur-reducing peptide fermenter of the archaeal phylum Crenarchaeota. It is the third heterotrophic, obligate sulfur reducing crenarchaeote to be sequenced and provides an opportunity for comparative analysis of the three genomes.


RESULTS
The 1.57 Mbp genome of the hyperthermophilic crenarchaeote Staphylothermus marinus has been completely sequenced. The main energy generating pathways likely involve 2-oxoacid:ferredoxin oxidoreductases and ADP-forming acetyl-CoA synthases. S. marinus possesses several enzymes not present in other crenarchaeotes including a sodium ion-translocating decarboxylase likely to be involved in amino acid degradation. S. marinus lacks sulfur-reducing enzymes present in the other two sulfur-reducing crenarchaeotes that have been sequenced -- Thermofilum pendens and Hyperthermus butylicus. Instead it has three operons similar to the mbh and mbx operons of Pyrococcus furiosus, which may play a role in sulfur reduction and/or hydrogen production. The two marine organisms, S. marinus and H. butylicus, possess more sodium-dependent transporters than T. pendens and use symporters for potassium uptake while T. pendens uses an ATP-dependent potassium transporter. T. pendens has adapted to a nutrient-rich environment while H. butylicus is adapted to a nutrient-poor environment, and S. marinus lies between these two extremes.


CONCLUSIONS
The three heterotrophic sulfur-reducing crenarchaeotes have adapted to their habitats, terrestrial vs. marine, via their transporter content, and they have also adapted to environments with differing levels of nutrients. Despite the fact that they all use sulfur as an electron acceptor, they are likely to have different pathways for sulfur reduction.
Anderson
Iain J
IJ
Genome Biology Program, Joint Genome Institute, Walnut Creek, USA. IJAnderson@lbl.gov
Dharmarajan
Lakshmi
L
Rodriguez
Jason
J
Hooper
Sean
S
Porat
Iris
I
Ulrich
Luke E
LE
Elkins
James G
JG
Mavromatis
Kostas
K
Sun
Hui
H
Land
Miriam
M
Lapidus
Alla
A
Lucas
Susan
S
Barry
Kerrie
K
Huber
Harald
H
Zhulin
Igor B
IB
Whitman
William B
WB
Mukhopadhyay
Biswarup
B
Woese
Carl
C
Bristow
James
J
Kyrpides
Nikos
N