TY - JOUR
T1 - Aspartic acid racemization and repair in the survival and recovery of hyperthermophiles after prolonged starvation at high temperature
AU - Liang, Renxing
AU - Robb, Frank T.
AU - Onstott, Tullis C.
N1 - Publisher Copyright:
© 2021 The Author(s) 2021. Published by Oxford University Press on behalf of FEMS. All rights reserved. For permissions, please e-mail: [email protected].
PY - 2021/9/1
Y1 - 2021/9/1
N2 - Long-term survivability is well-known for microorganisms in nutrient-depleted environments, but the damage accrued by proteins and the associated repair processes during the starvation and recovery phase of microbial life still remain enigmatic. We focused on aspartic acid (Asp) racemization and repair in the survival of Pyrococcus furiosus and Thermococcus litoralis under starvation conditions at high temperature. Despite the dramatic decrease of viability over time, 0.002% of P. furiosus cells (2.1×103 cells/mL) and 0.23% of T. litoralis cells (2.3×105 cells/mL) remained viable after 25 and 50 days, respectively. The D/L Asp ratio in the starved cells was approximately half of those from the autoclaved cells, suggesting that the starving cells were capable of partially repairing racemized Asp. Transcriptomic analyses of the recovered cells of T. litoralis indicated that the gene encoding Protein-L-isoaspartate (D-aspartate) O-methyltransferase (PIMT) might be involved in the repair of damaged proteins by converting D-Asp back to L-Asp during the resuscitation of starved cells. Collectively, our results provided evidence that Asp underwent racemization in the surviving hyperthermophilic cells under starved conditions and PIMT played a critical role in the repair of abnormal aspartyl residues during the initial recovery of starved, yet still viable, cells.
AB - Long-term survivability is well-known for microorganisms in nutrient-depleted environments, but the damage accrued by proteins and the associated repair processes during the starvation and recovery phase of microbial life still remain enigmatic. We focused on aspartic acid (Asp) racemization and repair in the survival of Pyrococcus furiosus and Thermococcus litoralis under starvation conditions at high temperature. Despite the dramatic decrease of viability over time, 0.002% of P. furiosus cells (2.1×103 cells/mL) and 0.23% of T. litoralis cells (2.3×105 cells/mL) remained viable after 25 and 50 days, respectively. The D/L Asp ratio in the starved cells was approximately half of those from the autoclaved cells, suggesting that the starving cells were capable of partially repairing racemized Asp. Transcriptomic analyses of the recovered cells of T. litoralis indicated that the gene encoding Protein-L-isoaspartate (D-aspartate) O-methyltransferase (PIMT) might be involved in the repair of damaged proteins by converting D-Asp back to L-Asp during the resuscitation of starved cells. Collectively, our results provided evidence that Asp underwent racemization in the surviving hyperthermophilic cells under starved conditions and PIMT played a critical role in the repair of abnormal aspartyl residues during the initial recovery of starved, yet still viable, cells.
KW - aspartic acid racemization
KW - hyperthermophiles
KW - protein-L-isoaspartate (D-aspartate) O-methyltransferase
KW - starvation
KW - survivability
KW - transcriptomics
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U2 - 10.1093/femsec/fiab112
DO - 10.1093/femsec/fiab112
M3 - Article
C2 - 34323966
AN - SCOPUS:85114363063
SN - 0168-6496
VL - 97
JO - FEMS microbiology ecology
JF - FEMS microbiology ecology
IS - 9
M1 - fiab112
ER -