GapMind for Amino acid biosynthesis

 

L-cysteine biosynthesis in Pedobacter sp. GW460-11-11-14-LB5

Best path

cysE, cysK

Also see fitness data for the top candidates

Rules

Overview: Cysteine biosynthesis in GapMind is based on MetaCyc pathways L-cysteine biosynthesis I from serine and sulfide (link), II (tRNA-dependent) (link), III from serine and homocysteine (link), V (protein-bound thiocarboxylates) (link), VIII via serine kinase (link), or IX via phosphoserine (link). There is no pathway IV. Pathway VI (from serine + methionine) is not included because it is not found in prototrophic bacteria. (It is found in H. pylori, which lacks biosynthesis of homocysteine or methionine; also, it is a supserset of the reactions in pathway III, from serine and homocysteine.) Pathway VII is not included because it requires sulfocysteine, an uncommon precursor. GapMind also describes cysteine biosynthesis with O-succinylserine as an intermediate (PMID:28581482), instead of O-acetylserine (as in pathway I).

15 steps (10 with candidates)

Or see definitions of steps

Step Description Best candidate 2nd candidate
cysE serine acetyltransferase CA265_RS10155 CA265_RS08175
cysK O-acetylserine sulfhydrylase CA265_RS10150 CA265_RS13740
Alternative steps:
CBS cystathionine beta-synthase CA265_RS04375 CA265_RS13740
CGL cystathionine gamma-lyase CA265_RS06375 CA265_RS08190
cysO sulfur carrier protein CysO
mec [CysO sulfur-carrier protein]-S-L-cysteine hydrolase
moeZ [sulfur carrier protein CysO]--sulfur ligase CA265_RS20190 CA265_RS12640
Mt_cysM CysO-thiocarboxylate-dependent cysteine synthase CA265_RS10150 CA265_RS04375
pscS Sep-tRNA:Cys-tRNA synthase
PSSH O-phosphoserine sulfhydrylase CA265_RS10150 CA265_RS04375
sepS O-phosphoseryl-tRNA ligase
serA 3-phosphoglycerate dehydrogenase CA265_RS09010 CA265_RS23175
serC 3-phosphoserine aminotransferase CA265_RS09005 CA265_RS03895
serK serine kinase (ADP-dependent)
SST serine O-succinyltransferase CA265_RS08175

Confidence: high confidence medium confidence low confidence
? – known gap: despite the lack of a good candidate for this step, this organism (or a related organism) performs the pathway

This GapMind analysis is from Aug 03 2021. The underlying query database was built on Aug 03 2021.

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About GapMind

Each pathway is defined by a set of rules based on individual steps or genes. Candidates for each step are identified by using ublast against a database of manually-curated proteins (most of which are experimentally characterized) or by using HMMer. Ublast hits may be split across two different proteins.

A candidate for a step is "high confidence" if either:

where "other" refers to the best ublast hit to a sequence that is not annotated as performing this step (and is not "ignored").

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. 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 the paper from 2019 on GapMind for amino acid biosynthesis, or view the source code, or see changes to Amino acid biosynthesis since the publication.

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