LTMB_EPIFI
ID LTMB_EPIFI Reviewed; 227 AA.
AC Q15FB1;
DT 23-MAY-2018, integrated into UniProtKB/Swiss-Prot.
DT 25-JUL-2006, sequence version 1.
DT 25-MAY-2022, entry version 19.
DE RecName: Full=Terpene cyclase ltmB {ECO:0000250|UniProtKB:Q0C8A7};
DE EC=4.2.3.- {ECO:0000250|UniProtKB:Q0C8A7};
DE AltName: Full=Lolitrem B biosynthesis cluster 2 protein B {ECO:0000303|PubMed:16765617};
GN Name=ltmB {ECO:0000303|PubMed:16765617};
OS Epichloe festucae var. lolii (Neotyphodium lolii) (Acremonium lolii).
OC Eukaryota; Fungi; Dikarya; Ascomycota; Pezizomycotina; Sordariomycetes;
OC Hypocreomycetidae; Hypocreales; Clavicipitaceae; Epichloe.
OX NCBI_TaxID=73839;
RN [1]
RP NUCLEOTIDE SEQUENCE [GENOMIC DNA], FUNCTION, AND PATHWAY.
RC STRAIN=Lp19;
RX PubMed=16765617; DOI=10.1016/j.fgb.2006.04.004;
RA Young C.A., Felitti S., Shields K., Spangenberg G., Johnson R.D.,
RA Bryan G.T., Saikia S., Scott B.;
RT "A complex gene cluster for indole-diterpene biosynthesis in the grass
RT endophyte Neotyphodium lolii.";
RL Fungal Genet. Biol. 43:679-693(2006).
RN [2]
RP FUNCTION.
RC STRAIN=Lp19;
RX PubMed=15991026; DOI=10.1007/s00438-005-1130-0;
RA Young C.A., Bryant M.K., Christensen M.J., Tapper B.A., Bryan G.T.,
RA Scott B.;
RT "Molecular cloning and genetic analysis of a symbiosis-expressed gene
RT cluster for lolitrem biosynthesis from a mutualistic endophyte of perennial
RT ryegrass.";
RL Mol. Genet. Genomics 274:13-29(2005).
RN [3]
RP INDUCTION.
RX PubMed=20519633; DOI=10.1104/pp.110.158451;
RA Eaton C.J., Cox M.P., Ambrose B., Becker M., Hesse U., Schardl C.L.,
RA Scott B.;
RT "Disruption of signaling in a fungal-grass symbiosis leads to
RT pathogenesis.";
RL Plant Physiol. 153:1780-1794(2010).
RN [4]
RP FUNCTION.
RX PubMed=22750140; DOI=10.1016/j.febslet.2012.06.035;
RA Saikia S., Takemoto D., Tapper B.A., Lane G.A., Fraser K., Scott B.;
RT "Functional analysis of an indole-diterpene gene cluster for lolitrem B
RT biosynthesis in the grass endosymbiont Epichloe festucae.";
RL FEBS Lett. 586:2563-2569(2012).
CC -!- FUNCTION: Terpene cyclase; part of the gene cluster that mediates the
CC biosynthesis of lolitrems, indole-diterpene mycotoxins that are potent
CC tremorgens in mammals, and are synthesized by clavicipitaceous fungal
CC endophytes in association with their grass hosts (PubMed:16765617). The
CC geranylgeranyl diphosphate (GGPP) synthase ltmG is proposed to catalyze
CC the first step in lolitrem biosynthesis (PubMed:16765617,
CC PubMed:15991026). LtmG catalyzes a series of iterative condensations of
CC isopentenyl diphosphate (IPP) with dimethylallyl diphosphate (DMAPP),
CC geranyl diphosphate (GPP), and farnesyl diphosphate (FPP), to form GGPP
CC (PubMed:16765617, PubMed:15991026). GGPP then condenses with indole-3-
CC glycerol phosphate to form 3-geranylgeranylindole, an acyclic
CC intermediate, to be incorporated into paxilline (PubMed:16765617).
CC Either ltmG or ltmC could be responsible for this step, as both are
CC putative prenyl transferases (PubMed:16765617). The FAD-dependent
CC monooxygenase ltmM then catalyzes the epoxidation of the two terminal
CC alkenes of the geranylgeranyl moiety, which is subsequently cyclized by
CC ltmB, to paspaline (PubMed:16765617, PubMed:15991026). The cytochrome
CC P450 monooxygenases ltmQ and ltmP can sequentially oxidize paspaline to
CC terpendole E and terpendole F (PubMed:22750140). Alternatively, ltmP
CC converts paspaline to an intermediate which is oxidized by ltmQ to
CC terpendole F (PubMed:22750140). LtmF, ltmK, ltmE and ltmJ appear to be
CC unique to the epichloe endophytes (PubMed:16765617, PubMed:15991026).
CC The prenyltransferase ltmF is involved in the 27-hydroxyl-O-prenylation
CC (PubMed:22750140). The cytochrome P450 monooxygenase ltmK is required
CC for the oxidative acetal ring formation (PubMed:22750140). The multi-
CC functional prenyltransferase ltmE is required for C20- and C21-
CC prenylations of the indole ring of paspalanes and acts together with
CC the cytochrome P450 monooxygenase ltmJ to yield lolitremanes by
CC multiple oxidations and ring closures (PubMed:22750140). The
CC stereoisomer pairs of lolitriol and lolitrem N or lolitrem B and
CC lolitrem F may be attributed to variations in the way in which ring
CC closure can occur under the action of ltmJ (PubMed:22750140). While the
CC major product of this pathway is lolitrem B, the prenyl transferases
CC and cytochrome P450 monooxygenases identified in this pathway have a
CC remarkable versatility in their regio- and stereo-specificities to
CC generate a diverse range of metabolites that are products of a
CC metabolic grid rather than a linear pathway (PubMed:22750140).
CC {ECO:0000269|PubMed:15991026, ECO:0000269|PubMed:16765617,
CC ECO:0000269|PubMed:22750140}.
CC -!- PATHWAY: Secondary metabolite biosynthesis.
CC {ECO:0000305|PubMed:16765617}.
CC -!- SUBCELLULAR LOCATION: Membrane {ECO:0000255}; Multi-pass membrane
CC protein {ECO:0000255}.
CC -!- INDUCTION: Expression is down-regulated when the stress-activated
CC mitogen-activated protein kinase (sakA) is deleted (PubMed:20519633).
CC {ECO:0000269|PubMed:20519633}.
CC -!- SIMILARITY: Belongs to the paxB family. {ECO:0000305}.
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DR EMBL; DQ443465; ABF20226.1; -; Genomic_DNA.
DR AlphaFoldDB; Q15FB1; -.
DR GO; GO:0016021; C:integral component of membrane; IEA:UniProtKB-KW.
DR GO; GO:0016829; F:lyase activity; IEA:UniProtKB-KW.
DR InterPro; IPR039020; PaxB-like.
DR PANTHER; PTHR42038; PTHR42038; 1.
PE 2: Evidence at transcript level;
KW Lyase; Membrane; Transmembrane; Transmembrane helix.
FT CHAIN 1..227
FT /note="Terpene cyclase ltmB"
FT /id="PRO_0000444323"
FT TRANSMEM 20..40
FT /note="Helical"
FT /evidence="ECO:0000255"
FT TRANSMEM 51..71
FT /note="Helical"
FT /evidence="ECO:0000255"
FT TRANSMEM 76..96
FT /note="Helical"
FT /evidence="ECO:0000255"
FT TRANSMEM 113..133
FT /note="Helical"
FT /evidence="ECO:0000255"
FT TRANSMEM 135..155
FT /note="Helical"
FT /evidence="ECO:0000255"
FT TRANSMEM 173..195
FT /note="Helical"
FT /evidence="ECO:0000255"
FT TRANSMEM 206..226
FT /note="Helical"
FT /evidence="ECO:0000255"
SQ SEQUENCE 227 AA; 25079 MW; 29422472A1546867 CRC64;
MDGFSNMEQA PLAYQEVQWL AETFVTFMGL GWLINYVLMI WHSRRGEPSS MALIPLCNNI
AWELVYTIIY PSPNKVELAA FIAGVTLNFL IMTSAARSAR SEWSHSPTMA KHAGLIIVAG
ILMCFTGHVA LAMEIGPALA YSWGAVICQL ALSIGGVCQL LQQHSTGGTS WKLWSSRFLG
SCCAVGFAFL RWRYWPEAYG WLASPLILWS LATFLVADLT YGVCLLL
