Differences

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--- strangeseqs [2026/01/16 10:37] – renefeyereisen
+++ strangeseqs [2026/03/22 13:56] (current) – renefeyereisen
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 **M-CLT2 - Cys-less type 2** evolved about 360 MYA in Heteroptera (“true bugs”), forming a monophyletic group of 17 sequences including CYP394A1 of //[[cimex_lectularius|Cimex lectularius]]//, CYP394B1 of //[[rhodnius_prolixus|Rhodnius prolixus]]// and CYP3221A1 of //Murgantia histrionica// belonging to the [[mito_clan|mito clan]] and closely related to CYP334 enzymes . These sequences lack the WxxxR motif but have ExxR and PERW motifs, yet lack a Cys pocket recognizable motif.
-**3-CLT3 - Cys-less type 3** is restricted to the aphid lineage (Aphidoidea - Adelgidae and Aphididae) and therefore evolved about 250MYA (Li et al., 2017). The aphid CYP6YC1 was initially called CYP6UN1 as a fragment in //Aphis gossypii//. While it has homologies with the CYP6 family, it is an odd member of the [[CYP3 clan|CYP3 clan]] outside the main (polyphyletic) CYP6 family. These sequences, found in single copies in at least 36 species are 30-40 codons shorter than most P450s. They have an N-terminal membrane-spanning region but miss parts of alpha helices B and C (no WxxxR motif), alpha F’ alpha G and H. They have ETLR in helix K, as well as the PxRF motif. The Cys pocket motif is truncated, and instead of the CYP2 clan typical PFxxGxRxCxG they have a P(H/Y)xxGxxSYIG motif with Tyr replacing Cys. This odd type of P450, while possibly tethered to the membrane, has a wide open active site with perhaps a large hydrophilic substrate. Mutants of CYP119 with Cys replaced by other amino acids can accomodate heme iron coordination (MacIntosh et al., 2015), and the aphid CYP6YC1 may therefore use either Tyr or the adjacent Ser (Coehlo et al., 2013) instead of the usual Cys as heme ligand. It is difficult to predict what type of reaction would be catalyzed by this P450.
+**3-CLT3 - Cys-less type 3** is restricted to the aphid lineage (Aphidoidea - Adelgidae and Aphididae) and therefore evolved about 250MYA (Li et al., 2017). The aphid CYP6YC1 was initially called CYP6UN1 as a fragment in //Aphis gossypii//. While it has homologies with the CYP6 family, it is an odd member of the [[CYP3 clan|CYP3 clan]] outside the main (polyphyletic) CYP6 family. These sequences, found in single copies in at least 36 species are 30-40 codons shorter than most P450s. They have an N-terminal membrane-spanning region but miss parts of alpha helices B and C (no WxxxR motif), alpha F’ alpha G and H. They have ETLR in helix K, as well as the PxRF motif. The Cys pocket motif is truncated, and instead of the CYP3 clan typical PFxxGxRxCxG they have a P(H/Y)xxGxxSYIG motif with Tyr replacing Cys. This odd type of P450, while possibly tethered to the membrane, has a wide open active site with perhaps a large hydrophilic substrate. Mutants of CYP119 with Cys replaced by other amino acids can accomodate heme iron coordination (MacIntosh et al., 2015), and the aphid CYP6YC1 may therefore use either Tyr or the adjacent Ser (Coehlo et al., 2013) instead of the usual Cys as heme ligand. It is difficult to predict what type of reaction would be catalyzed by this P450.
 **3-CLT4 - Cys-less type 4**, derived from the CYP6 family, evolved about 220 MYA in a coleopteran clade that includes Tenebrionoidea, Cucujoidea and the “Phytophaga” (Chrysomeloidea and Curculionoidae). It includes CYP393A1 of //[[dendroctonus_ponderosae|Dendroctonus ponderosae]]// and CYP348A1 of //[[tribolium|Tribolium castaneum]]//. These short sequences found in at least 23 species have the ETLR and PDRF motifs and a conserved I helix lacking the usual Thr, and also lack the Cys in the heme binding pocket.