Periplasmic dipeptide-binding protein: Difference between revisions
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www.who.int/news-room/fact-sheets/detail/tuberculosis.</ref>. Being that iron is relatively scarce within alveolar macrophage phagosomes, Mtb has evolved intricate means by which iron is uptaken. The sheer number of genes dedicated to these processes is an indication of the complex evolution of this uptake. For instance, ''M. tuberculosis'' have approximately 35 known genes alone associated only with the production of salicylate-derivative iron siderophores termed mycobactins<ref>DOI: 10.1086/518040</ref>. | www.who.int/news-room/fact-sheets/detail/tuberculosis.</ref>. Being that iron is relatively scarce within alveolar macrophage phagosomes, Mtb has evolved intricate means by which iron is uptaken. The sheer number of genes dedicated to these processes is an indication of the complex evolution of this uptake. For instance, ''M. tuberculosis'' have approximately 35 known genes alone associated only with the production of salicylate-derivative iron siderophores termed mycobactins<ref>DOI: 10.1086/518040</ref>. | ||
== Heme Transport Into | == Heme Transport Into Mtb == | ||
''M. tuberculosis'' has a two-membrane exterior, composed of a peptidoglycan exterior membrane and an interior cell membrane. Heme transport into the periplasmic space has been understood for some time in that several integral proteins used in the transport of heme from the extracellular matrix into the periplasmic space have been elucidated, specifically PPE36, PPE22, and PPE62<ref name=Alex>DOI: 10.1038/s41467-019-12109-5</ref>. DppA is a type of periplasmic binding protein specific to ''M. tuberculosis''. | ''M. tuberculosis'' has a two-membrane exterior, composed of a peptidoglycan exterior membrane and an interior cell membrane. Heme transport into the periplasmic space has been understood for some time in that several integral proteins used in the transport of heme from the extracellular matrix into the periplasmic space have been elucidated, specifically PPE36, PPE22, and PPE62<ref name=Alex>DOI: 10.1038/s41467-019-12109-5</ref>. DppA is a type of periplasmic binding protein specific to ''M. tuberculosis''. | ||
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Researchers have elucidated a few other heme binding PBPs which are functionally similar to DppA of Mtb. ShuT of ''S. dysenteriae'' and PhuT of ''P. aeruginosa'' were among the earliest of these proteins to be elucidated in 2007<ref name=Bob/>. A general mechanism has been proposed for the activity of these proteins, but these proteins differ significantly structurally from DppA, so it is unlikely the specific mechanism of these proteins relates to DppA<ref name=Bob>DOI: 10.1074/jbc.M706761200</ref>. | Researchers have elucidated a few other heme binding PBPs which are functionally similar to DppA of Mtb. ShuT of ''S. dysenteriae'' and PhuT of ''P. aeruginosa'' were among the earliest of these proteins to be elucidated in 2007<ref name=Bob/>. A general mechanism has been proposed for the activity of these proteins, but these proteins differ significantly structurally from DppA, so it is unlikely the specific mechanism of these proteins relates to DppA<ref name=Bob>DOI: 10.1074/jbc.M706761200</ref>. | ||
== DPP System in | == DPP System in Mtb == | ||
The DPP system in Mtb is used for influx of heme across the cellular membrane. DppA is a member of the DPP system in Mtb. DppA transports heme across the periplasmic space of Mtb to the DppBCD transporter, which likely transfers the heme across the membrane as has been seen with other substrate-binding proteins of ABC transporters<ref name=Alex/>. Research has shown the DPP complex is not involved in heme detoxification, but rather is involved in the import of heme across the cell membrane<ref name=Alex/>. | The DPP system in Mtb is used for influx of heme across the cellular membrane. DppA is a member of the DPP system in Mtb. DppA transports heme across the periplasmic space of Mtb to the DppBCD transporter, which likely transfers the heme across the membrane as has been seen with other substrate-binding proteins of ABC transporters<ref name=Alex/>. Research has shown the DPP complex is not involved in heme detoxification, but rather is involved in the import of heme across the cell membrane<ref name=Alex/>. | ||