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== Function == | == Function == | ||
[[http://www.uniprot.org/uniprot/HPBD_PARDP HPBD_PARDP]] Catalyzes the 2-epimerization of trans-4-hydroxy-L-proline betaine (tHyp-B) to cis-4-hydroxy-D-proline betaine (cHyp-B). Is involved in a catabolic pathway that degrades tHyp-B to alpha-ketoglutarate. This pathway would permit the utilization of tHyp-B as a carbon and nitrogen source in the absence of osmotic stress, since tHyp-B functions as an osmolyte and is not catabolized when it is needed as osmoprotectant. Can also catalyze the racemization of L-proline betaine.<ref>PMID:24056934</ref> | [[http://www.uniprot.org/uniprot/HPBD_PARDP HPBD_PARDP]] Catalyzes the 2-epimerization of trans-4-hydroxy-L-proline betaine (tHyp-B) to cis-4-hydroxy-D-proline betaine (cHyp-B). Is involved in a catabolic pathway that degrades tHyp-B to alpha-ketoglutarate. This pathway would permit the utilization of tHyp-B as a carbon and nitrogen source in the absence of osmotic stress, since tHyp-B functions as an osmolyte and is not catabolized when it is needed as osmoprotectant. Can also catalyze the racemization of L-proline betaine.<ref>PMID:24056934</ref> | ||
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== Publication Abstract from PubMed == | |||
UNLABELLED: Through the use of genetic, enzymatic, metabolomic, and structural analyses, we have discovered the catabolic pathway for proline betaine, an osmoprotectant, in Paracoccus denitrificans and Rhodobacter sphaeroides. Genetic and enzymatic analyses showed that several of the key enzymes of the hydroxyproline betaine degradation pathway also function in proline betaine degradation. Metabolomic analyses detected each of the metabolic intermediates of the pathway. The proline betaine catabolic pathway was repressed by osmotic stress and cold stress, and a regulatory transcription factor was identified. We also report crystal structure complexes of the P. denitrificans HpbD hydroxyproline betaine epimerase/proline betaine racemase with l-proline betaine and cis-hydroxyproline betaine. IMPORTANCE: At least half of the extant protein annotations are incorrect, and the errors propagate as the number of genome sequences increases exponentially. A large-scale, multidisciplinary sequence- and structure-based strategy for functional assignment of bacterial enzymes of unknown function has demonstrated the pathway for catabolism of the osmoprotectant proline betaine. | |||
Prediction and biochemical demonstration of a catabolic pathway for the osmoprotectant proline betaine.,Kumar R, Zhao S, Vetting MW, Wood BM, Sakai A, Cho K, Solbiati J, Almo SC, Sweedler JV, Jacobson MP, Gerlt JA, Cronan JE MBio. 2014 Feb 11;5(1):e00933-13. doi: 10.1128/mBio.00933-13. PMID:24520058<ref>PMID:24520058</ref> | |||
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.<br> | |||
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== References == | == References == | ||
<references/> | <references/> | ||
Revision as of 23:04, 24 January 2018
Crystal structure of an enolase (mandelate racemase subgroup) from paracococus denitrificans pd1222 (target nysgrc-012907) with bound l-proline betaine (substrate)Crystal structure of an enolase (mandelate racemase subgroup) from paracococus denitrificans pd1222 (target nysgrc-012907) with bound l-proline betaine (substrate)
Structural highlights
Function[HPBD_PARDP] Catalyzes the 2-epimerization of trans-4-hydroxy-L-proline betaine (tHyp-B) to cis-4-hydroxy-D-proline betaine (cHyp-B). Is involved in a catabolic pathway that degrades tHyp-B to alpha-ketoglutarate. This pathway would permit the utilization of tHyp-B as a carbon and nitrogen source in the absence of osmotic stress, since tHyp-B functions as an osmolyte and is not catabolized when it is needed as osmoprotectant. Can also catalyze the racemization of L-proline betaine.[1] Publication Abstract from PubMedUNLABELLED: Through the use of genetic, enzymatic, metabolomic, and structural analyses, we have discovered the catabolic pathway for proline betaine, an osmoprotectant, in Paracoccus denitrificans and Rhodobacter sphaeroides. Genetic and enzymatic analyses showed that several of the key enzymes of the hydroxyproline betaine degradation pathway also function in proline betaine degradation. Metabolomic analyses detected each of the metabolic intermediates of the pathway. The proline betaine catabolic pathway was repressed by osmotic stress and cold stress, and a regulatory transcription factor was identified. We also report crystal structure complexes of the P. denitrificans HpbD hydroxyproline betaine epimerase/proline betaine racemase with l-proline betaine and cis-hydroxyproline betaine. IMPORTANCE: At least half of the extant protein annotations are incorrect, and the errors propagate as the number of genome sequences increases exponentially. A large-scale, multidisciplinary sequence- and structure-based strategy for functional assignment of bacterial enzymes of unknown function has demonstrated the pathway for catabolism of the osmoprotectant proline betaine. Prediction and biochemical demonstration of a catabolic pathway for the osmoprotectant proline betaine.,Kumar R, Zhao S, Vetting MW, Wood BM, Sakai A, Cho K, Solbiati J, Almo SC, Sweedler JV, Jacobson MP, Gerlt JA, Cronan JE MBio. 2014 Feb 11;5(1):e00933-13. doi: 10.1128/mBio.00933-13. PMID:24520058[2] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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