GapMind for Amino acid biosynthesis

 

L-methionine biosynthesis in Methylohalobius crimeensis 10Ki

Best path

asp-kinase, asd, hom, metA, metZ, metH, B12-reactivation-domain

Rules

Overview: Methionine biosynthesis in GapMind is based on MetaCyc pathways L-methionine biosynthesis I via O-succinylhomoserine and cystathionine (link), II via O-phosphohomoserine and cystathionine (link), III via O-acetylhomoserine (link), or IV with reductive sulfhydrylation of aspartate semialdehyde (link). These pathways vary in how aspartate semialdehyde is reduced and sulfhydrylated to homocysteine. GapMind does not represent the formation of the methyl donors for methionine synthase, such as 5-methyltetrahydrofolate or methyl corrinoid proteins.

27 steps (16 with candidates)

Or see definitions of steps

Step Description Best candidate 2nd candidate
asp-kinase aspartate kinase H035_RS0101685 H035_RS0106110
asd aspartate semi-aldehyde dehydrogenase H035_RS0104810
hom homoserine dehydrogenase H035_RS0111190 H035_RS0101685
metA homoserine O-succinyltransferase H035_RS0106255
metZ O-succinylhomoserine sulfhydrylase H035_RS0108840
metH vitamin B12-dependent methionine synthase H035_RS0106295
B12-reactivation-domain MetH reactivation domain H035_RS0106295
Alternative steps:
asd-S-ferredoxin L-aspartate semialdehyde sulfurtransferase, NIL/ferredoxin component H035_RS0105020
asd-S-perS L-aspartate semialdehyde sulfurtransferase, persulfide-forming component
asd-S-transferase L-aspartate semialdehyde sulfurtransferase, persulfide component
hom_kinase homoserine kinase H035_RS0111500
mesA Methylcobalamin:homocysteine methyltransferase MesA
mesB Methylcobalamin:homocysteine methyltransferase MesB
mesC Methylcobalamin:homocysteine methyltransferase MesC
mesD oxygen-dependent methionine synthase, methyltransferase component MesD
mesX oxygen-dependent methionine synthase, putative oxygenase component MesX
metB cystathionine gamma-synthase H035_RS0108840
metC cystathionine beta-lyase H035_RS0108840
metE vitamin B12-independent methionine synthase H035_RS0105140
metX homoserine O-acetyltransferase H035_RS0106255
metY O-acetylhomoserine sulfhydrylase H035_RS0108840
ramA ATP-dependent reduction of co(II)balamin
split_metE_1 vitamin B12-independent methionine synthase, folate-binding component
split_metE_2 vitamin B12-independent methionine synthase, catalytic component H035_RS0105140
split_metH_1 Methionine synthase component, B12 binding and B12-binding cap domains H035_RS0106295
split_metH_2 Methionine synthase component, methyltransferase domain
split_metH_3 Methionine synthase component, pterin-binding domain

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 Jul 25 2024. The underlying query database was built on Jul 25 2024.

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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 (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:

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. 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