Protein target profile

VK055_3519

serine O-acetyltransferase

Genome: KpATCC43816 Gene: cysE AIK82075.1 3D evidence: Experimental + ColabFold model Metabolism 1 reaction UniProt A6TFK2

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Length 273

Pocket druggability 0.415

Metabolic reactions 1

Chokepoint No

Direct ligand evidence 0 53 total records

Functional annotation 0 EC 4 GO

Target summary

Strong target candidate with converging metabolic, structural and chemical evidence.

Automated synthesis of the evidence currently loaded. Review the underlying records before prioritizing this protein.

Main supporting evidence

Experimental structure available At least one PDB experimental structure is loaded, not just a predicted model - stronger structural coverage than AlphaFold/ColabFold alone. Central metabolic position More central than 93.0% of genes in this genome. No isoenzyme backup detected Imported GPR rules do not show an alternative enzyme for the catalyzed reaction set. No similar human protein detected The current BLAST sequence screen did not find a significant human match, lowering apparent off-target risk. Review the complete evidence below

Risks to review

Evidence coverage

Core evidence streams are available for this target.

Terms and data sources used on this page

PDB: experimentally determined structures from the Protein Data Bank. These are the strongest structural evidence, but may cover only part of the protein.

AlphaFold DB model: a precomputed predicted structure downloaded from AlphaFold Database/UniProt, not an experiment performed here.

ColabFold model: a predicted structure generated for this workspace; interpret it with coverage and confidence.

pLDDT: confidence score for predicted structures. High values support local geometry; low values mean the region should not drive pocket interpretation.

FPocket / P2Rank: software tools that predict possible ligand-binding pockets on a 3D structure. They are useful screening signals, not experimental validation.

Druggability: a pocket-based estimate of whether a small molecule could bind productively. It does not mean a drug already exists.

PDB ligand: a compound observed in an experimental structure. Direct same-protein records are stronger than homolog-transferred records.

ChEMBL: a public database of measured compound bioactivity. Direct entries are stronger than entries transferred from similar proteins.

ZINC: a purchasable-compound database. Here it marks proposed candidates from chemical similarity, not measured binders.

LigQ / LigQ_2: an internal Target pipeline step that gathers PDB, ChEMBL, and ZINC ligand evidence for each protein.

Off-target: sequence similarity to proteins we prefer not to hit, such as human proteins or beneficial gut microbiome proteins.

DEG: Database of Essential Genes. A match suggests the protein resembles genes known to be essential in other organisms.

Roary / CoreCruncher: pan-genome tools used to decide whether a gene is core across analyzed strains or accessory/strain-specific.

EC / GO: functional annotations: EC describes enzyme reactions; GO describes biological process, molecular function, or cellular component.

KEGG pathway: a curated metabolic route label used here to group reactions imported from the metabolic model.

Chokepoint: a metabolic reaction that is the only producer or consumer of a metabolite in the imported model.

Prioritization evidence

Selectivity, essentiality, structural confidence, conservation, and predicted binding-site evidence.

Off-target risk

Human off-target: No hit
Gut microbiome similarity: 4.0% of screened genomes Lower prevalence suggests narrower overlap with the screened gut microbiome.

Essentiality

Essential (DEG): Y
DEG identity (%): 95.604 Higher values support similarity to known essential genes.
DEG E-value: 0.0 Smaller values mean stronger essential-gene similarity.

Localization

Localization: Cytoplasmic

Structure confidence

ColabFold pLDDT: 95.44 0-100 confidence; >70 supports local structural interpretation.

Binding-site evidence

PDB experimental structure

The selected pocket score is the FPocket value used for ranking after applying the curated structure priority. It estimates small-molecule pocket quality; it is not experimental binding evidence. The 3D viewer may show a different loaded structure, so visible pockets can differ.

FPocket 0.415

Structure 6JVU

Pocket Pocket 4

P2Rank 0.061

Structure 6JVU

Pocket Pocket 1

ColabFold model

FPocket 0.511 · Pocket 15

P2Rank 0.185 · Pocket 1

Core conservation Conserved core gene

Roary core

CoreCruncher core

Gut microbiome 188 / 4744 genomes with a hit

Prevalence 4.0%

Cross-references

External database identifiers for this protein, its structures, ligands, and metabolic reactions.

Metabolic context

Reactions catalyzed, pathway membership, and centrality in the genome-scale metabolic network.

Explore metabolic network

Metabolic context: more central than 93.0% of genes in this genome, no human homolog detected.

Relative network centrality 93.0% more central than 93.0% of genes in this genome

Chokepoint Not a chokepoint

Imported from KpATCC43816.sbml · 2026-07-09

Sequence

Primary amino-acid sequence viewer.

MPCEELDIVWNNIKAEARALADCEPMLASFYHATLLKHENLGSALSYMLANKLASPIMPAIAIREVVEEAYAADPEMIASAACDIQAVRTRDPAVDKYSTPLLYLKGFHALQAYRIGHWLWTQGRRALAIFLQNQVSVSFQVDIHPAAKIGRGIMLDHATGIVVGETAVIEDDVSILQSVTLGGTGKTSGDRHPKIREGVMIGAGAKILGNIEVGRGAKIGAGSVVLQPVPPHTTAAGVPARIVGKPESDKPAMDMDQHFNGIHHTFEYGDGI

Functional annotations

Enzyme classification and Gene Ontology terms linked to this protein.

4 GO

Gene Ontology (GO)

GO:0009001 Catalysis of the reaction: L-serine + acetyl-CoA = O-acetyl-L-serine + CoA.
GO:0005737 The contents of a cell excluding the plasma membrane and nucleus, but including other subcellular structures.
GO:0006535 OBSOLETE. The chemical reactions and pathways resulting in the formation of cysteine from L- serine.
GO:0016740 Catalysis of the transfer of a group, e.g. a methyl group, glycosyl group, acyl group, phosphorus-containing, or other groups, from one compound (generally regarded as the donor) to another compound (generally regarded as the acceptor). Transferase is the systematic name for any enzyme of EC class 2.

Sequence domains and features

Domain and signature matches imported from InterPro and related databases.

19 records

Show feature table

Start	End	DB	Term	Name
140	240	CDD	cd03354	LbH_SAT
140	240	InterPro	IPR045304	Serine acetyltransferase, LbH domain
202	230	ProSitePatterns	PS00101	Hexapeptide-repeat containing-transferases signature.
202	230	InterPro	IPR018357	Hexapeptide transferase, conserved site
193	226	Pfam	PF00132	Bacterial transferase hexapeptide (six repeats)
193	226	InterPro	IPR001451	Hexapeptide repeat
9	113	SMART	SM00971	SATase_N_2_a
9	113	InterPro	IPR010493	Serine acetyltransferase, N-terminal
143	273	Gene3D	G3DSA:2.160.10.10	Hexapeptide repeat proteins
143	264	FunFam	G3DSA:2.160.10.10:FF:000002	Serine acetyltransferase
4	260	SUPERFAMILY	SSF51161	Trimeric LpxA-like enzymes
4	260	InterPro	IPR011004	Trimeric LpxA-like superfamily
9	113	Pfam	PF06426	Serine acetyltransferase, N-terminal
1	142	Gene3D	G3DSA:1.10.3130.10	serine acetyltransferase, domain 1
1	142	InterPro	IPR042122	Serine acetyltransferase, N-terminal domain superfamily
4	258	PANTHER	PTHR42811	SERINE ACETYLTRANSFERASE
1	142	FunFam	G3DSA:1.10.3130.10:FF:000001	Acetyltransferase
82	242	NCBIfam	TIGR01172	serine O-acetyltransferase
82	242	InterPro	IPR005881	Serine O-acetyltransferase

3D structure

Selected loaded structure. Experimental PDB entries may cover only a portion of the sequence; AlphaFold DB and ColabFold models typically cover the full protein but remain computational predictions.

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Pocket score High Medium Low

How colors and pocket overlays are used

Uniform protein color marks the displayed model as a single molecular object.

Experimental PDB structures may be colored by chain to distinguish subunits or copies present in the file.

Pocket colors and alpha spheres are evidence overlays for predicted binding cavities; they are not alternative protein chains.

'Alpha spheres' is FPocket's own cavity-shape geometry, imported when available and aligned with the loaded structure.

'Pocket atoms'/'Predicted site atoms' show the pocket's residue atoms instead: P2Rank reports residues rather than alpha spheres, and FPocket falls back to this when alpha-sphere geometry is unavailable or doesn't align.

'No pocket geometry' means neither alpha spheres nor residue-position data could be found for that pocket; the layer just highlights the same residues as 'Nearby residues'.

Pocket details Inspect a specific pocket, or open the full viewer

Binding pockets · FPocket

Druggability: high ≥ 0.7 · medium 0.4–0.69 · low < 0.4

Site 1 FPocket #4

0.415

Likely same site as P2Rank 1 7.3 Å 2 shared residues 20% of smaller site

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Surrounding area

Site 2 FPocket #1

0.381

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Surrounding area

Binding pockets · P2Rank

Probability: high ≥ 0.5 · medium 0.2–0.49 · low < 0.2

Site 1 P2Rank #1

0.061

Likely same site as FPocket 4 7.3 Å 2 shared residues 20% of smaller site

Show in viewer

Surrounding area

Binding pockets · P2Rank

Probability: high ≥ 0.5 · medium 0.2–0.49 · low < 0.2

Site 1 P2Rank #1

0.185

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Surrounding area

Site 2 P2Rank #2

0.167

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Surrounding area

Site 3 P2Rank #3

0.013

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Surrounding area

All structural evidence 1 experimental · 1 predicted

Structural evidence

1 + 1

Experimental PDB entries plus predicted AlphaFold DB or ColabFold models. Click Switch to display a different loaded structure in the viewer.

Entry	Method	Resolution	Chain	Coverage	Links	Status
PDB 6JVU	X-ray	—	A	—	PDBe RCSB PDBj File	Viewing
ColabFold VK055_3519	ColabFold	—	—	full sequence	—	Loaded

Ligand evidence

Ligands grouped by evidence source. PDB ligands keep the source crystal visible, and loaded crystals can be opened directly in the structure viewer.

53 records

Chemistry signal

Structural ligand evidence is available for this target.

Direct evidence 0 same-protein records

Transferred evidence 3 records from similar proteins

Structural ligands 3 0 loaded crystals

Measured bioactivity 0 direct and transferred ChEMBL records

Proposed compounds 50 similarity-based ZINC candidates

Best available ligand signal

15P PDB via homolog 1529.8 Da · LogP 0.17 · TPSA 334.1 Open detail RCSB PDB

OAS PDB via homolog Detail RCSB PDB

PG5 PDB via homolog Detail RCSB PDB

ZINC1580161 ZINC proposed compound · Tanimoto 1.000 Detail ZINC

ZINC16052118 ZINC proposed compound · Tanimoto 1.000 Detail ZINC

Highest-confidence structural evidence: ligands co-crystallized with this exact protein. If the source PDB is loaded in Target, use Open crystal to inspect it in the structure viewer.

No PDB structure with a co-crystallized ligand found for this exact protein.

Structural evidence inferred from similar proteins. The source crystal indicates where the ligand was observed; the UniProt column identifies the homologous protein carrying that ligand.

Ligand	Source crystal	UniProt (homolog)	MW · LogP · TPSA	Lipinski	PAINS	SMILES
15P RCSB PDB	4HZD	A0A0F6AR69	1529.8 Da LogP 0.17 TPSA 334.1	2 viol.	✓ Clean	`COCCOCCOCCOCCOCCOCCOCCOCCOCCOCCOCCOCCOCCOCCOCCO…`
OAS RCSB PDB	4ZU1	P29847	147.1 Da LogP -1.04 TPSA 89.6	✓ Ro5	✓ Clean	`CC(=O)OC[C@@H](C(=O)O)N`
PG5 RCSB PDB	3GVD	A0A2U2H3H7	178.2 Da LogP 0.31 TPSA 36.9	✓ Ro5	✓ Clean	`COCCOCCOCCOC`

Experimental bioactivity from ChEMBL measured directly on this protein. Score = pchembl (−log Ki/IC₅₀; higher = more potent).

No ChEMBL bioactivity data found for this exact protein.

Bioactivity inferred from similar proteins in ChEMBL. Score = pchembl (−log Ki/IC₅₀; higher = more potent).

No ChEMBL hits found through similar proteins.

Proposed virtual-screening candidates from ZINC. Score = Tanimoto similarity to a known binder (0–1; higher = more similar).

Ligand	Tanimoto	MW · LogP · TPSA	Lipinski	PAINS	SMILES
ZINC1580161 ZINC	1.000	208.3 Da LogP -0.33 TPSA 57.2	✓ Ro5	✓ Clean	`COCCOCCOCCOCCO`
ZINC16052118 ZINC	1.000	340.4 Da LogP -0.28 TPSA 84.8	✓ Ro5	✓ Clean	`COCCOCCOCCOCCOCCOCCOCCO`
ZINC16052257 ZINC	1.000	384.5 Da LogP -0.26 TPSA 94.1	✓ Ro5	✓ Clean	`COCCOCCOCCOCCOCCOCCOCCOCCO`
ZINC34317654 ZINC	1.000	472.6 Da LogP -0.23 TPSA 112.5	1 viol.	✓ Clean	`COCCOCCOCCOCCOCCOCCOCCOCCOCCOCCO`
ZINC44076059 ZINC	1.000	428.5 Da LogP -0.24 TPSA 103.3	✓ Ro5	✓ Clean	`COCCOCCOCCOCCOCCOCCOCCOCCOCCO`
ZINC5210101 ZINC	1.000	252.3 Da LogP -0.31 TPSA 66.4	✓ Ro5	✓ Clean	`COCCOCCOCCOCCOCCO`
ZINC5997860 ZINC	1.000	296.4 Da LogP -0.29 TPSA 75.6	✓ Ro5	✓ Clean	`COCCOCCOCCOCCOCCOCCO`
ZINC575419714 ZINC	0.727	312.4 Da LogP 0.42 TPSA 66.4	✓ Ro5	✓ Clean	`COCCOCCOCCSCCOCCOCCO`
ZINC115163232 ZINC	0.700	222.3 Da LogP 0.07 TPSA 57.2	✓ Ro5	✓ Clean	`COCCOCCOCCOCCCO`
ZINC258837490 ZINC	0.700	354.4 Da LogP 0.11 TPSA 84.8	✓ Ro5	✓ Clean	`COCCOCCOCCOCCOCCOCCOCCCO`
ZINC1692489 ZINC	0.688	222.3 Da LogP 0.33 TPSA 46.2	✓ Ro5	✓ Clean	`COCCOCCOCCOCCOC`
ZINC4530388 ZINC	0.688	266.3 Da LogP 0.35 TPSA 55.4	✓ Ro5	✓ Clean	`COCCOCCOCCOCCOCCOC`
ZINC5701172 ZINC	0.688	310.4 Da LogP 0.36 TPSA 64.6	✓ Ro5	✓ Clean	`COCCOCCOCCOCCOCCOCCOC`
ZINC5997861 ZINC	0.688	398.5 Da LogP 0.40 TPSA 83.1	✓ Ro5	✓ Clean	`COCCOCCOCCOCCOCCOCCOCCOCCOC`
ZINC1706207 ZINC	0.583	202.2 Da LogP 0.32 TPSA 69.7	✓ Ro5	✓ Clean	`CC(=O)OCC(COC(C)=O)C(C)=O`
ZINC34111591 ZINC	0.583	207.3 Da LogP -1.06 TPSA 62.2	✓ Ro5	✓ Clean	`COCCOCCN(CCO)CCO`
ZINC100017163 ZINC	0.553	213.3 Da LogP 0.71 TPSA 99.2	✓ Ro5	✓ Clean	`C/C=C/CC(=N)NCCC[C@H](N)C(=O)O`
ZINC19796052 ZINC	0.553	219.2 Da LogP -1.73 TPSA 156.9	✓ Ro5	✓ Clean	`N/C(=N\[N+](=O)[O-])NCCC[C@H](N)C(=O)O`
ZINC21982226 ZINC	0.553	219.2 Da LogP -1.73 TPSA 156.9	✓ Ro5	✓ Clean	`N/C(=N\[N+](=O)[O-])NCCC[C@@H](N)C(=O)O`
ZINC34764844 ZINC	0.550	206.3 Da LogP 1.09 TPSA 36.9	✓ Ro5	✓ Clean	`CCCOCCOCCOCCOC`
ZINC2383745924 ZINC	0.542	398.5 Da LogP -0.01 TPSA 94.1	✓ Ro5	✓ Clean	`COCCOCCOCCOCC(CO)COCCOCCOCCOC`
ZINC5131766 ZINC	0.538	224.3 Da LogP -1.26 TPSA 92.4	✓ Ro5	✓ Clean	`N[C@@H](CS)C(=O)N[C@@H](CS)C(=O)O`
ZINC1529646 ZINC	0.526	290.3 Da LogP -1.78 TPSA 185.8	1 viol.	✓ Clean	`N=C(NCCC[C@H](N)C(=O)O)N[C@@H](CC(=O)O)C(=O)O`
ZINC2043460 ZINC	0.526	214.3 Da LogP -0.52 TPSA 111.2	✓ Ro5	✓ Clean	`C=CCNC(=N)NCCC[C@H](N)C(=O)O`
ZINC3105913 ZINC	0.526	240.2 Da LogP 1.22 TPSA 54.0	✓ Ro5	✓ Clean	`COCCOCP(C)(=O)COCCOC`
ZINC115086873 ZINC	0.524	209.2 Da LogP -1.08 TPSA 83.2	✓ Ro5	✓ Clean	`NOCCOCCOCCOCCO`
ZINC140264883 ZINC	0.524	223.3 Da LogP -0.43 TPSA 72.2	✓ Ro5	✓ Clean	`COCCOCCOCCOCCON`
ZINC146143823 ZINC	0.524	237.3 Da LogP -1.00 TPSA 83.2	✓ Ro5	✓ Clean	`NCCOCCOCCOCCOCCO`
ZINC1565503710 ZINC	0.524	254.3 Da LogP -0.03 TPSA 57.2	✓ Ro5	✓ Clean	`OCCOCCOCCOCCOCCS`
ZINC1730666 ZINC	0.524	208.2 Da LogP -1.46 TPSA 126.6	✓ Ro5	✓ Clean	`N[C@@H](CSC[C@H](N)C(=O)O)C(=O)O`
ZINC1730667 ZINC	0.524	208.2 Da LogP -1.46 TPSA 126.6	✓ Ro5	✓ Clean	`N[C@H](CSC[C@H](N)C(=O)O)C(=O)O`
ZINC1730669 ZINC	0.524	208.2 Da LogP -1.46 TPSA 126.6	✓ Ro5	✓ Clean	`N[C@H](CSC[C@@H](N)C(=O)O)C(=O)O`
ZINC3055005 ZINC	0.524	204.2 Da LogP -0.63 TPSA 126.6	✓ Ro5	✓ Clean	`N[C@@H](CCCC[C@H](N)C(=O)O)C(=O)O`
ZINC3055007 ZINC	0.524	204.2 Da LogP -0.63 TPSA 126.6	✓ Ro5	✓ Clean	`N[C@@H](CCCC[C@@H](N)C(=O)O)C(=O)O`
ZINC3055010 ZINC	0.524	204.2 Da LogP -0.63 TPSA 126.6	✓ Ro5	✓ Clean	`N[C@H](CCCC[C@@H](N)C(=O)O)C(=O)O`
ZINC33358855 ZINC	0.524	207.3 Da LogP -0.36 TPSA 62.9	✓ Ro5	✓ Clean	`COCCOCCOCCOCCN`
ZINC38917157 ZINC	0.524	210.3 Da LogP -0.04 TPSA 47.9	✓ Ro5	✓ Clean	`OCCOCCOCCOCCS`
ZINC44583772 ZINC	0.524	356.5 Da LogP 0.66 TPSA 64.6	✓ Ro5	✓ Clean	`COCCOCCOCCOCCOCCOCCOCCS`
ZINC5024003 ZINC	0.524	251.3 Da LogP -0.34 TPSA 72.2	✓ Ro5	✓ Clean	`COCCOCCOCCOCCOCCN`
ZINC575432090 ZINC	0.524	355.4 Da LogP -0.38 TPSA 99.9	✓ Ro5	✓ Clean	`COCCOCCOCCOCCOCCOCCOCCON`
ZINC575432265 ZINC	0.524	399.5 Da LogP -0.36 TPSA 109.1	✓ Ro5	✓ Clean	`COCCOCCOCCOCCOCCOCCOCCOCCON`
ZINC71254558 ZINC	0.524	444.6 Da LogP 0.70 TPSA 83.1	✓ Ro5	✓ Clean	`COCCOCCOCCOCCOCCOCCOCCOCCOCCS`
ZINC83253921 ZINC	0.524	369.5 Da LogP -0.95 TPSA 110.9	✓ Ro5	✓ Clean	`NCCOCCOCCOCCOCCOCCOCCOCCO`
ZINC83253930 ZINC	0.524	224.3 Da LogP 0.61 TPSA 36.9	✓ Ro5	✓ Clean	`COCCOCCOCCOCCS`
ZINC83253936 ZINC	0.524	383.5 Da LogP -0.29 TPSA 99.9	✓ Ro5	✓ Clean	`COCCOCCOCCOCCOCCOCCOCCOCCN`
ZINC90556279 ZINC	0.524	295.4 Da LogP -0.33 TPSA 81.4	✓ Ro5	✓ Clean	`COCCOCCOCCOCCOCCOCCN`
ZINC90556287 ZINC	0.524	268.4 Da LogP 0.63 TPSA 46.2	✓ Ro5	✓ Clean	`COCCOCCOCCOCCOCCS`
ZINC90741446 ZINC	0.524	386.5 Da LogP 0.02 TPSA 84.8	✓ Ro5	✓ Clean	`OCCOCCOCCOCCOCCOCCOCCOCCS`
ZINC90741447 ZINC	0.524	298.4 Da LogP -0.01 TPSA 66.4	✓ Ro5	✓ Clean	`OCCOCCOCCOCCOCCOCCS`
ZINC96503353 ZINC	0.524	471.6 Da LogP -0.26 TPSA 118.3	1 viol.	✓ Clean	`COCCOCCOCCOCCOCCOCCOCCOCCOCCOCCN`

PDB and ChEMBL records on this protein are shown in full. ChEMBL records from similar proteins are capped at the top 100 per protein (by pchembl) and ZINC at the top 50 (Tanimoto ≥ 0.5). ADME columns are descriptor-based screening flags, not experimental toxicity results.

VK055_3519

Strong target candidate with converging metabolic, structural and chemical evidence.

Main supporting evidence

Risks to review

Evidence coverage

Prioritization evidence

Off-target risk

Essentiality

Localization

Structure confidence

Binding-site evidence

Cross-references

Sequence

Structure

Pathways

Metabolic context

Sequence

Functional annotations

Gene Ontology (GO)

Sequence domains and features

3D structure

Binding pockets · FPocket

Binding pockets · P2Rank

Binding pockets · FPocket

Binding pockets · P2Rank

Structural evidence

Ligand evidence