As text, or see rules and steps
# Putrescine degradation in GapMind is based on MetaCyc pathways # putrescine degradation I via putrescine aminotransferase (metacyc:PUTDEG-PWY), # pathway II with glutamylated intermediates (metacyc:PWY0-1221), # pathway IV via putrescine oxidase (metacyc:PWY-2), # or pathway V via putrescine:pyruvate aminotransferase (metacyc:PWY-3). # Pathway III is not reported in prokaryotes, so it is not included in GapMind. # ABC transporters: # 4-part ABC transporters include E. coli potABCD or potGHIF, which are related to each other, and a related system, # also named potABCD, from Streptococcus pneuomoniae. potA putrescine ABC transporter, ATPase component (PotA/PotG) curated:TCDB::P31134 curated:CharProtDB::CH_024626 curated:TCDB::Q97Q42 potB putrescine ABC transporter, permease component 1 (PotB/PotH) curated:CharProtDB::CH_088338 curated:CharProtDB::CH_088337 curated:TCDB::Q97Q43 potC putrescine ABC transporter, permease component 2 (PotC/PotI) curated:CharProtDB::CH_088340 curated:SwissProt::P0AFL1 curated:TCDB::Q97Q44 # SpuD from P. aeruginosa (Q02UB7) is similar and was shown to bind putrescine potD putrescine ABC transporter, substrate-binding component (PotD/PotF) curated:CharProtDB::CH_088339 curated:SwissProt::P31133 curated:TCDB::Q97Q45 curated:SwissProt::Q02UB7 # Transporters were identified using: # query: transporter:putrescine putrescine-transport: potA potB potC potD # Homomeric transporters: puuP putrescine:H+ symporter PuuP/PlaP curated:SwissProt::P0AA47 curated:SwissProt::P76037 putrescine-transport: puuP potE putrescine:H+ symporter PotE curated:SwissProt::P0AAF1 putrescine-transport: potE TPO1 putrescine transporter TPO1 curated:CharProtDB::CH_091011 putrescine-transport: TPO1 UGA4 putrescine transporter UGA4 curated:CharProtDB::CH_091303 putrescine-transport: UGA4 POT1 putrescine:H+ symporter POT1 curated:TCDB::Q5C8V6 putrescine-transport: POT1 # Ignored export systems, including sapBCDF, and the agmatine/putrescine antiporter AguD # Gamma-aminobutyrate is a common intermediate, and can be oxidized to succinate # via succinate semialdehyde # Sama_2636 (A1S8Y2) was added because it is a transaminase involved in putrescine utilization gabT gamma-aminobutyrate transaminase EC:2.6.1.19 EC:2.6.1.96 uniprot:A1S8Y2 # This may be either NADH or NADPH dependent, forming succinate in either case. # Close homologs in Pseudomonas or Klebsiella are annotated as glutarate-semialdehyde dehydrogenases (1.2.1.20) # or aldehyde dehydrogenases (1.2.1.3); Q9I6M5 is annotated as glutarate-semialdehyde dehydrogenase # but with no EC number. # Q8BUF0 appears to be misannotated in BRENDA. gabD succinate semialdehyde dehydrogenase EC:1.2.1.79 EC:1.2.1.24 EC:1.2.1.16 ignore:BRENDA::Q8BUF0 ignore_other:1.2.1.20 ignore_other:1.2.1.3 ignore:SwissProt::Q9I6M5 # GABA (4-aminobutanoate) is consumed by an aminotransferase (known as gabT or puuE), which forms # succinate semialdehyde, and dehydrogenase gabD, which forms succinate. GABA-degradation: gabT gabD # Since patA and putrescine-pyruvate transaminase (spuC) perform similar reactions and # produce gamma-aminobutyraldehyde (4-aminobutanal), they are listed together. # Many close homologs of patA are GABA aminotransferases (EC 2.6.1.19), so ignore those. patA putrescine aminotransferase (PatA/SpuC) EC:2.6.1.82 curated:metacyc::MONOMER-17 EC:2.6.1.113 ignore_other:2.6.1.19 patD gamma-aminobutyraldehyde dehydrogenase EC:1.2.1.19 # In pathway I or pathway V, putrescine aminotransferase (patA or spuC) forms 4-aminobutanal, # and dehydrogenase patD forms GABA. putrescine-to-GABA: patA patD puuA glutamate-putrescine ligase EC:6.3.1.11 # MetaCyc uses EC 1.4.3.M3; other resources uses 1.4.3.- puuB gamma-glutamylputrescine oxidase term:glutamylputrescine oxidase # The putative kauB (4-guanidinobutyraldehyde dehydrogenase) from P. putida (metacyc::MONOMER-11560) # is included because it is closely related to P. aeruginosa kauB (PA5312), which acts on # gamma-glutamyl-gamma-aminobutyraldehyde as well (PMID:3141581). # Some other P. fluorescens kauB-type proteins seem to be acting in this pathway # but were annotated with EC:1.2.1.54 instead, so these were added manually. puuC gamma-glutamyl-gamma-aminobutyraldehyde dehydrogenase EC:1.2.1.99 curated:metacyc::MONOMER-11560 curated:reanno::pseudo13_GW456_L13:PfGW456L13_805 curated:reanno::pseudo6_N2E2:Pf6N2E2_4383 curated:reanno::pseudo5_N2C3_1:AO356_12580 curated:reanno::WCS417:GFF5420 puuD gamma-glutamyl-gamma-aminobutyrate hydrolase EC:3.5.1.94 # In pathway II, putrescine is converted to GABA with glutamylated intermedates: # puuA forms gamma-glutamyl-putrescine, an oxidase forms 4-(gamma-glutaminylamino)butanal, # a dehydrogenase forms 4-(gamma-glutamylamino)butanoate, and a hydrolase releases # glutamate and GABA. putrescine-to-GABA: puuA puuB puuC puuD puo putrescine oxidase EC:1.4.3.10 # As part of pathway IV, putrescine oxidase (puo) forms 4-aminobutanal, # which is probably converted to GABA by dehydrogenase patD. putrescine-to-GABA: puo patD # Gamma-aminobutyrate is a common intermediate. putrescine-degradation: putrescine-to-GABA GABA-degradation all: putrescine-transport putrescine-degradation
Each pathway is defined by a set of rules based on individual steps or genes. Candidates for each step are identified by using ublast (a fast alternative to protein BLAST) against a database of manually-curated proteins (most of which are experimentally characterized) or by using HMMer with enzyme models (usually from TIGRFam). Ublast hits may be split across two different proteins.
A candidate for a step is "high confidence" if either:
Otherwise, a candidate is "medium confidence" if either:
Other blast hits with at least 50% coverage are "low confidence."
Steps with no high- or medium-confidence candidates may be considered "gaps." For the typical bacterium that can make all 20 amino acids, there are 1-2 gaps in amino acid biosynthesis pathways. For diverse bacteria and archaea that can utilize a carbon source, there is a complete high-confidence catabolic pathway (including a transporter) just 38% of the time, and there is a complete medium-confidence pathway 63% of the time. Gaps may be due to:
GapMind relies on the predicted proteins in the genome and does not search the six-frame translation. In most cases, you can search the six-frame translation by clicking on links to Curated BLAST for each step definition (in the per-step page).
For more information, see:
If you notice any errors or omissions in the step descriptions, or any questionable results, please let us know
by Morgan Price, Arkin group, Lawrence Berkeley National Laboratory