Walton JD

References (6)

Title : Peptide macrocyclization catalyzed by a prolyl oligopeptidase involved in alpha-amanitin biosynthesis - Luo_2014_Chem.Biol_21_1610
Author(s) : Luo H , Hong SY , Sgambelluri RM , Angelos E , Li X , Walton JD
Ref : Chemical Biology , 21 :1610 , 2014
Abstract : Amatoxins are ribosomally encoded and posttranslationally modified peptides that account for the majority of fatal mushroom poisonings of humans. A representative amatoxin is the bicyclic octapeptide alpha-amanitin, formed via head-to-tail macrocyclization, which is ribosomally biosynthesized as a 35-amino acid propeptide in Amanita bisporigera and in the distantly related mushroom Galerina marginata. Although members of the prolyl oligopeptidase (POP) family of serine proteases have been proposed to play a role in alpha-amanitin posttranslational processing, the exact mechanistic details are not known. Here, we show that a specific POP (GmPOPB) is required for toxin maturation in G. marginata. Recombinant GmPOPB catalyzed two nonprocessive reactions: hydrolysis at an internal Pro to release the C-terminal 25-mer from the 35-mer propeptide and transpeptidation at the second Pro to produce the cyclic octamer. On the other hand, we show that GmPOPA, the putative housekeeping POP of G. marginata, behaves like a conventional POP.
ESTHER : Luo_2014_Chem.Biol_21_1610
PubMedSearch : Luo_2014_Chem.Biol_21_1610
PubMedID: 25484237

Title : Extensive sampling of basidiomycete genomes demonstrates inadequacy of the white-rot\/brown-rot paradigm for wood decay fungi - Riley_2014_Proc.Natl.Acad.Sci.U.S.A_111_9923
Author(s) : Riley R , Salamov AA , Brown DW , Nagy LG , Floudas D , Held BW , Levasseur A , Lombard V , Morin E , Otillar R , Lindquist EA , Sun H , LaButti KM , Schmutz J , Jabbour D , Luo H , Baker SE , Pisabarro AG , Walton JD , Blanchette RA , Henrissat B , Martin F , Cullen D , Hibbett DS , Grigoriev IV
Ref : Proc Natl Acad Sci U S A , 111 :9923 , 2014
Abstract : Basidiomycota (basidiomycetes) make up 32% of the described fungi and include most wood-decaying species, as well as pathogens and mutualistic symbionts. Wood-decaying basidiomycetes have typically been classified as either white rot or brown rot, based on the ability (in white rot only) to degrade lignin along with cellulose and hemicellulose. Prior genomic comparisons suggested that the two decay modes can be distinguished based on the presence or absence of ligninolytic class II peroxidases (PODs), as well as the abundance of enzymes acting directly on crystalline cellulose (reduced in brown rot). To assess the generality of the white-rot/brown-rot classification paradigm, we compared the genomes of 33 basidiomycetes, including four newly sequenced wood decayers, and performed phylogenetically informed principal-components analysis (PCA) of a broad range of gene families encoding plant biomass-degrading enzymes. The newly sequenced Botryobasidium botryosum and Jaapia argillacea genomes lack PODs but possess diverse enzymes acting on crystalline cellulose, and they group close to the model white-rot species Phanerochaete chrysosporium in the PCA. Furthermore, laboratory assays showed that both B. botryosum and J. argillacea can degrade all polymeric components of woody plant cell walls, a characteristic of white rot. We also found expansions in reducing polyketide synthase genes specific to the brown-rot fungi. Our results suggest a continuum rather than a dichotomy between the white-rot and brown-rot modes of wood decay. A more nuanced categorization of rot types is needed, based on an improved understanding of the genomics and biochemistry of wood decay.
ESTHER : Riley_2014_Proc.Natl.Acad.Sci.U.S.A_111_9923
PubMedSearch : Riley_2014_Proc.Natl.Acad.Sci.U.S.A_111_9923
PubMedID: 24958869
Gene_locus related to this paper: pleos-a0a067nlj6 , 9agar-a0a067t0n0 , 9agar-a0a067sha0 , 9homo-a0a067pav0 , pleos-a0a067n337 , 9homo-a0a067pz82 , 9homo-a0a067m7p7 , pleos-a0a067p245 , 9homo-a0a067lrz6 , 9homo-a0a067m4r5 , 9homo-a0a067mr63 , 9homo-a0a067mrq8 , 9agar-a0a067t4j6 , 9homo-a0a067pdz2 , 9homo-a0a067q2n9 , 9agar-a0a067tsx5 , 9homo-a0a067mfq5 , 9homo-a0a067qc90 , pleos-a0a067p113 , 9homo-a0a067pwi6 , 9agar-a0a067s6d7 , 9agar-a0a067tie7 , pleos-a0a067ngc3 , 9agar-a0a067st69 , 9agar-a0a067t6h9 , 9agar-a0a067tj80 , pleos-a0a067npl2 , 9agar-a0a067sm07 , 9agar-a0a067tar9 , 9agar-a0a067tid6 , 9agar-a0a067u335 , pleos-a0a067ndv5 , pleos-a0a067nqw6 , 9homo-a0a067pkj2 , 9agar-a0a067t683 , 9homo-a0a067mgl1 , 9agar-a0a067sg35 , 9homo-a0a067q7g6 , 9agar-a0a067tub0 , 9agar-a0a067t8f5 , 9agar-a0a067tj19 , 9homo-a0a067pyu9 , 9agar-a0a067tjp8 , 9agar-a0a067sjg9 , 9agar-a0a067u0h4 , pleos-a0a067nxe9 , 9agar-a0a067sqt2 , 9agar-a0a067tgx3 , 9homo-a0a067psv8 , 9agar-a0a067sq58 , 9homo-a0a067m4m0 , 9agar-a0a067tqz5 , pleos-a0a067new9 , 9homo-a0a067m9v3 , 9agar-a0a067tlx5 , 9agar-a0a067tfq4 , pleos-a0a067nln4 , pleos-a0a067ndf5 , pleos-a0a067nn26 , pleos-a0a067nfv2 , 9homo-a0a067pnd3 , 9agar-a0a067sw48 , pleos-a0a067neg3 , pleos-a0a067nz51 , pleos-a0a067naf9 , pleos-a0a067nad7 , 9agar-a0a067sxe2 , 9agar-a0a067slu3 , pleos-a0a067n7p8 , pleos-a0a067nl60 , pleos-a0a067ncd0 , 9agar-a0a067th99 , 9agar-a0a067sp22 , pleos-a0a067pbw7 , 9homo-a0a067q916 , 9homo-a0a067pwe5 , galm3-a0a067scb0 , galm3-popa

Title : Ribosomal biosynthesis of alpha-amanitin in Galerina marginata - Luo_2012_Fungal.Genet.Biol_49_123
Author(s) : Luo H , Hallen-Adams HE , Scott-Craig JS , Walton JD
Ref : Fungal Genet Biol , 49 :123 , 2012
Abstract : Amatoxins, including alpha-amanitin, are bicyclic octapeptides found in mushrooms (Agaricomycetes, Agaricales) of certain species in the genera Amanita, Galerina, Lepiota, and Conocybe. Amatoxins and the chemically similar phallotoxins are synthesized on ribosomes in Amanita bisporigera, Amanita phalloides, and Amanita ocreata. In order to determine if amatoxins are synthesized by a similar mechanism in another, distantly related mushroom, we obtained genome survey sequence data from a monokaryotic isolate of Galerinamarginata, which produces alpha-amanitin. The genome of G. marginata contains two copies of the alpha-amanitin gene (GmAMA1-1 and GmAMA1-2). The alpha-amanitin proprotein sequences of G. marginata (35 amino acids) are highly divergent from AMA1 of A. bisporigera except for the toxin region itself (IWGIGCNP in single-letter amino acid code) and the amino acids immediately upstream (N[A/S]TRLP). G. marginata does not contain any related toxin-encoding sequences besides GmAMA1-1 and GmAMA1-2. DNA from two other alpha-amanitin-producing isolates of Galerina (G. badipes and G. venenata) hybridized to GmAMA1, whereas DNA from the toxin non-producing species Galerinahybrida did not. Expression of the GmAMA1 genes was induced by growth on low carbon. RNASeq evidence indicates that both copies of GmAMA1 are expressed approximately equally. A prolyl oligopeptidase (POP) is strongly implicated in processing of the cyclic peptide toxins of A. bisporigera and Conocybe apala. G. marginata has two predicted POP genes; one, like AbPOPB of A. bisporigera, is present only in the toxin-producing isolates of Galerina and the other, like AbPOPA of A. bisporigera, is present in all species. Our results indicate that G.marginata biosynthesizes amatoxins on ribosomes by a pathway similar to Amanita species, involving a genetically encoded proprotein of 35 amino acids that is post-translationally processed by a POP. However, due to the high degree of divergence, the evolutionary relationship between AMA1 in the genera Amanita and Galerina is unclear.
ESTHER : Luo_2012_Fungal.Genet.Biol_49_123
PubMedSearch : Luo_2012_Fungal.Genet.Biol_49_123
PubMedID: 22202811
Gene_locus related to this paper: galm3-popa

Title : Colocalization of amanitin and a candidate toxin-processing prolyl oligopeptidase in Amanita basidiocarps - Luo_2010_Eukaryot.Cell_9_1891
Author(s) : Luo H , Hallen-Adams HE , Scott-Craig JS , Walton JD
Ref : Eukaryot Cell , 9 :1891 , 2010
Abstract : Fungi in the basidiomycetous genus Amanita owe their high mammalian toxicity to the bicyclic octapeptide amatoxins such as alpha-amanitin. Amatoxins and the related phallotoxins (such as the heptapeptide phalloidin) are encoded by members of the "MSDIN" gene family and are synthesized on ribosomes as short (34- to 35-amino-acid) proproteins. Antiamanitin antibodies and confocal microscopy were used to determine the cellular and subcellular localizations of amanitin accumulation in basidiocarps (mushrooms) of the Eastern North American destroying angel (Amanita bisporigera). Consistent with previous studies, amanitin is present throughout the basidiocarp (stipe, pileus, lamellae, trama, and universal veil), but it is present in only a subset of cells within these tissues. Restriction of amanitin to certain cells is especially marked in the hymenium. Several lines of evidence implicate a specific prolyl oligopeptidase, A. bisporigera POPB (AbPOPB), in the initial processing of the amanitin and phallotoxin proproteins. The gene for AbPOPB is restricted taxonomically to the amatoxin-producing species of Amanita and is clustered in the genome with at least one expressed member of the MSDIN gene family. Immunologically, amanitin and AbPOPB show a high degree of colocalization, indicating that toxin biosynthesis and accumulation occur in the same cells and possibly in the same subcellular compartments.
ESTHER : Luo_2010_Eukaryot.Cell_9_1891
PubMedSearch : Luo_2010_Eukaryot.Cell_9_1891
PubMedID: 20889720
Gene_locus related to this paper: amabi-popb , amabi-popa

Title : Processing of the phalloidin proprotein by prolyl oligopeptidase from the mushroom Conocybe albipes - Luo_2009_J.Biol.Chem_284_18070
Author(s) : Luo H , Hallen-Adams HE , Walton JD
Ref : Journal of Biological Chemistry , 284 :18070 , 2009
Abstract : The peptide toxins of poisonous Amanita mushrooms are bicyclic octapeptides (amatoxins) or heptapeptides (phallotoxins). In Amanita bisporigera, alpha-amanitin and phallacidin are synthesized as 35- and 34-amino acid proproteins, respectively, in which the amino acid sequences found in the mature toxins are flanked by conserved amino acid sequences. The presence of invariant Pro residues immediately upstream of the toxin regions and as the last predicted amino acid in the toxin regions themselves suggests that a Pro-specific peptidase is responsible for the initial post-translational processing of the Amanita toxin proproteins. We purified an enzyme from the phalloidin-producing mushroom Conocybe albipes that cleaves a synthetic 22-mer phalloidin peptide to release the mature toxin peptide (AWLATCP). Mass spectrometric analysis of the purified protein combined with isolation and sequencing of the encoding gene indicates that the responsible processing enzyme is a member of the prolyl oligopeptidase (POP) subfamily of proteases (EC 3.4.21.26). The processing enzyme was able to use the chromogenic POP substrate benzyloxycarbonyl-Gly-Pro-p-nitroanilide and was inhibited by the specific POP inhibitor benzyloxycarbonyl-Pro-prolinal. Both Pro bonds in the proprotein are cleaved by the same enzyme, with the C-terminal Pro bond cleaved first or much faster than the N-terminal Pro bond. Transient accumulation of the N-terminal intermediate indicates that cleavage is not strongly processive. A synthetic peptide representing the phallacidin proprotein was also cleaved by the POP of C. albipes, but a precursor of amanitin (which is not made by C. albipes) was cleaved inefficiently.
ESTHER : Luo_2009_J.Biol.Chem_284_18070
PubMedSearch : Luo_2009_J.Biol.Chem_284_18070
PubMedID: 19389704

Title : The Fusarium graminearum genome reveals a link between localized polymorphism and pathogen specialization - Cuomo_2007_Science_317_1400
Author(s) : Cuomo CA , Guldener U , Xu JR , Trail F , Turgeon BG , Di Pietro A , Walton JD , Ma LJ , Baker SE , Rep M , Adam G , Antoniw J , Baldwin T , Calvo S , Chang YL , Decaprio D , Gale LR , Gnerre S , Goswami RS , Hammond-Kosack K , Harris LJ , Hilburn K , Kennell JC , Kroken S , Magnuson JK , Mannhaupt G , Mauceli E , Mewes HW , Mitterbauer R , Muehlbauer G , Munsterkotter M , Nelson D , O'Donnell K , Ouellet T , Qi W , Quesneville H , Roncero MI , Seong KY , Tetko IV , Urban M , Waalwijk C , Ward TJ , Yao J , Birren BW , Kistler HC
Ref : Science , 317 :1400 , 2007
Abstract : We sequenced and annotated the genome of the filamentous fungus Fusarium graminearum, a major pathogen of cultivated cereals. Very few repetitive sequences were detected, and the process of repeat-induced point mutation, in which duplicated sequences are subject to extensive mutation, may partially account for the reduced repeat content and apparent low number of paralogous (ancestrally duplicated) genes. A second strain of F. graminearum contained more than 10,000 single-nucleotide polymorphisms, which were frequently located near telomeres and within other discrete chromosomal segments. Many highly polymorphic regions contained sets of genes implicated in plant-fungus interactions and were unusually divergent, with higher rates of recombination. These regions of genome innovation may result from selection due to interactions of F. graminearum with its plant hosts.
ESTHER : Cuomo_2007_Science_317_1400
PubMedSearch : Cuomo_2007_Science_317_1400
PubMedID: 17823352
Gene_locus related to this paper: fusof-f9fxz4 , gibze-a8w610 , gibze-b1pdn0 , gibze-i1r9e6 , gibze-i1rda9 , gibze-i1rdk7 , gibze-i1rec8 , gibze-i1rgs0 , gibze-i1rgy0 , gibze-i1rh52 , gibze-i1rhi8 , gibze-i1rig9 , gibze-i1rip5 , gibze-i1rpg6 , gibze-i1rsg2 , gibze-i1rv36 , gibze-i1rxm5 , gibze-i1rxp8 , gibze-i1rxv5 , gibze-i1s1u3 , gibze-i1s3j9 , gibze-i1s6l7 , gibze-i1s8i8 , gibze-i1s9x4 , gibze-ppme1 , gibze-q4huy1 , gibze-i1rg17 , gibze-i1rb76 , gibze-i1s1m7 , gibze-i1s3z6 , gibze-i1rd78 , gibze-i1rgl9 , gibze-i1rjp7 , gibze-i1s1q6 , gibze-i1ri35 , gibze-i1rf76 , gibze-i1rhp3 , gibza-a0a016pda4 , gibza-a0a016pl96 , gibze-i1rjb5 , gibze-i1rkc4 , gibze-a0a1c3ylb1 , gibze-gra11 , gibze-fsl2