Rv3550 (echA20)

Current annotations:
- TBCAP: (community-based annotations - see table at bottom of page)
- TBDB: enoyl-CoA hydratase
- REFSEQ: enoyl-CoA hydratase
- PATRIC: Probable enoyl-CoA hydratase EchA20 (EC 4.2.1.17)
- TUBERCULIST: Probable enoyl-CoA hydratase EchA20 (enoyl hydrase) (unsaturated acyl-CoA hydratase) (crotonase)
- NCBI: Probable enoyl-CoA hydratase EchA20 (enoyl hydrase) (unsaturated acyl-CoA hydratase) (crotonase)
- updated information (H37Rv4):
  - gene name: echA20
  - function:
  - reference:
Coordinates in H37Rv: 3989153 - 3989896
Gene length: 744 bp (with stop codon), 247 aa (without stop codon)
Operon:

Trans-membrane region:
Role: I.A.3 - Fatty acids
GO terms:
- GO:0008152 - metabolic process (Uniprot)
- GO:0006635 - fatty acid beta-oxidation (Uniprot)
- GO:0004300 - enoyl-CoA hydratase activity (Uniprot)
- GO:0003824 - catalytic activity (Uniprot)
Reaction(s) (based on iSM810 metabolic model):
Gene Expression Profile (Transcriptional Responses to Drugs; Boshoff et al, 2004)
Gene Modules extracted from cluster analysis of 249 transcriptomic datasets using ICA
Orthologs among selected mycobacteria
Protein structure:
Search for Latest Homologs in PDB

Top 10 Homologs in PDB (as of Apr 2026):

PDB	aa ident	species	PDB title
4JWV	38%	Novosphingobium aromaticivorans	Crystal Structure of putative short chain enoyl-CoA hydratase from Novosphingobium aromaticivorans DSM 12444
7MCM	37%	Mycolicibacterium smegmatis	Crystal Structure of Enoyl-CoA hydratase from Mycolicibacterium smegmatis

Links to additional information on echA20:
- TBDB (updated)
- Phyre2 structure prediction, model: final.casp.pdb (from Mao et al, 2013)
- UniProt
- AlphaFold model
- Vulnerability = 0.716 (from Jeremy Rock's lab)
- KEGG - nucleotide and amino acid sequences of gene
- Mycobrowser
- PATRIC
- BioCyc
- Systems Biology

Amino Acid Sequence

MPITSTTPEPGIVAVTVDYPPVNAIPSKAWFDLADAVTAAGANSDTRAVILRAEGRGFNAGVDIKEMQRTEGFTALIDANRGCFAAFRAVYECAVPVIAA
VNGFCVGGGIGLVGNSDVIVASEDATFGLPEVERGALGAATHLSRLVPQHLMRRLFFTAATVDAATLQHFGSVHEVVSRDQLDEAALRVARDIAAKDTRV
IRAAKEALNFIDVQRVNASYRMEQGFTFELNLAGVADEHRDAFVKKS

(Nucleotide sequence available on KEGG)

Additional Information

ESSENTIALITY

MtbTnDB - interactive tool for exploring a database of published TnSeq datasets for Mtb

TnSeqCorr - genes with correlated TnSeq profiles across ~100 conditions

Rv3550/echA20, gene len: 743 bp, num TA sites: 6

condition	dataset	call	medium	method	notes
in-vitro	DeJesus 2017 mBio	non-essential	7H9	HMM	fully saturated, 14 TnSeq libraries combined
in-vitro	Sassetti 2003 Mol Micro	non-essential	7H9	TRASH	essential if hybridization ratio<0.2
in-vivo (mice)	Sassetti 2003 PNAS	no data	BL6 mice	TRASH	essential if hybridization ratio<0.4, min over 4 timepoints (1-8 weeks)
in-vitro (glycerol)	Griffin 2011 PPath	non-essential	M9 minimal+glycerol	Gumbel	2 replicates; Padj<0.05
in-vitro (cholesterol)	Griffin 2011 PPath	uncertain	M9 minimal+cholesterol	Gumbel	3 replicates; Padj<0.05
differentially essential in cholesterol	Griffin 2011 PPath	NO (LFC=-5.72)	cholesterol vs glycerol	resampling-SR	YES if Padj<0.05, else not significant; LFC<0 means less insertions/more essential in cholesterol
in-vitro	Smith 2022 eLife	growth defect	7H9	HMM	6 replicates (raw data in Subramaniam 2017, PMID 31752678)
in-vivo (mice)	Smith 2022 eLife	growth defect	BL6 mice	HMM	6 replicates (raw data in Subramaniam 2017, PMID 31752678)
differentially essential in mice	Smith 2022 eLife	NO (LFC=-1.516)	in-vivo vs in-vitro	ZINB	YES if Padj<0.05, else not significant; LFC<0 means less insertions/more essential in mice
in-vitro (minimal)	Minato 2019 mSys	non-essential	minimal medium	HMM
in-vitro (YM rich medium)	Minato 2019 mSys	non-essential	YM rich medium	HMM	7H9 supplemented with ~20 metabolites (amino acids, cofactors)
differentially essential in YM rich medium	Minato 2019 mSys	NO (LFC=-2.03)	YM rich vs minimal medium	resampling

Analysis of Positive Selection in Clinical Isolates new

data from Culviner et al (2025) (55,259 Mtb clinical isolates)
- overall pN/pS for Rv3550: 0.522960097
- lineage-specific pN/pS in L1: 0.410048258
- lineage-specific pN/pS in L2: 0.46143538
- lineage-specific pN/pS in L3: 0.58833011
- lineage-specific pN/pS in L4: 0.579803586

Analysis of dN/dS (omega) in a global collection of 10k Mtb clinical isolates using GenomegaMap (Window model)
clinical isolates collection: global set of 10,626 Mtb genomes
In the omega plots, the black line shows the mean estimate of omega (dN/dS) at each codon, and the blue lines are the bounds for the 95% credible interval (95%CI, from MCMC sampling).
A gene is under significant positive selection if the lower-bound of the 95%CI of omega (lower blue line) exceeds 1.0 at any codon.

	global set of 10,626 Mtb clinical isolates
under significant positive selection?	NO
omega peak height (95%CI lower bound)	1.32 (0.54)
codons under selection
omega plots
genetic variants*	link

* example format for variants: "D27 (GAC): D27H (CAC,11)" means "Asp27 (native codon GAC) mutated to His (codon CAC) in 11 isolates"

TnSeq Data No data currently available.

No TnSeq data currently available for this Target.

RNASeq Data No data currently available.

No RNA-Seq data currently available for this Target.

Metabolomic Profiles No data currently available.

No Metabolomic data currently available for this Target.

Proteomic Data No data currently available.

No Proteomic data currently available for this Target.

Regulatory Relationships from Systems Biology

BioCyc

Gene interactions based on ChIPSeq and Transcription Factor Over-Expression (TFOE) (Systems Biology)

NOTE: see table of TFOE interactions below

Interactions based on ChIPSeq data

Binds To:
- No bindings to other targets were found.
Bound By:

Interactions based on ChIPSeq data (Minch et al. 2014)

Binds To:
- No bindings to other targets were found.
Bound By:
- Rv3557c (-) (Direct binding)

Interactions based on TFOE data (Rustad et al. 2014)

TFOE = Transcription Factor Over-Expression study
significance criteria used in paper: greater than 2-fold change (|LFC|>=1.0) and Padj<0.01

gene	dysregulated by OE of	LFC
Rv3550/echA20	Rv2250c/-	1.43
Rv3550/echA20	Rv0260c/nnaR	1.36
Rv3550/echA20	Rv0078/-	-1.16
Rv3550/echA20	Rv1990c/-	-1.45
Rv3550/echA20	Rv0328/-	-1.66
Rv3550/echA20	Rv3557c/kstR2	-2.28

Upregulates:
- Does not upregulate other genes.
Upregulated by:
- Rv0260c (-)
- Rv2250c (-)
Downregulates:
- Does not downregulate other genes.
Downregulated by:

Property	Value	Creator	Evidence	Comment
Interaction	RegulatedBy Rv3416	yamir.moreno	IDA	One hybrid reporter system. Physical binding of the regulator to the regulated promoter proved by using electrophoretic mobility shift assay. . M. Guo, H. Feng et al. Dissecting transcription regulatory pathways through a new bacterial one-hybrid reporter system. Genome Res. 2009
Interaction	RegulatedBy Rv3334	yamir.moreno	IDA	One hybrid reporter system. Physical binding of the regulator to the regulated promoter proved by using electrophoretic mobility shift assay. . M. Guo, H. Feng et al. Dissecting transcription regulatory pathways through a new bacterial one-hybrid reporter system. Genome Res. 2009
Interaction	RegulatedBy Rv2175c	yamir.moreno	IDA	One hybrid reporter system. Physical binding of the regulator to the regulated promoter proved by using electrophoretic mobility shift assay. . M. Guo, H. Feng et al. Dissecting transcription regulatory pathways through a new bacterial one-hybrid reporter system. Genome Res. 2009
Interaction	RegulatedBy Rv1956	yamir.moreno	IDA	One hybrid reporter system. Physical binding of the regulator to the regulated promoter proved by using electrophoretic mobility shift assay. . M. Guo, H. Feng et al. Dissecting transcription regulatory pathways through a new bacterial one-hybrid reporter system. Genome Res. 2009
Interaction	RegulatedBy Rv1931c	yamir.moreno	IDA	One hybrid reporter system. Physical binding of the regulator to the regulated promoter proved by using electrophoretic mobility shift assay. . M. Guo, H. Feng et al. Dissecting transcription regulatory pathways through a new bacterial one-hybrid reporter system. Genome Res. 2009
Interaction	RegulatedBy Rv0823c	yamir.moreno	IDA	One hybrid reporter system. Physical binding of the regulator to the regulated promoter proved by using electrophoretic mobility shift assay. . M. Guo, H. Feng et al. Dissecting transcription regulatory pathways through a new bacterial one-hybrid reporter system. Genome Res. 2009
Interaction	RegulatedBy Rv0445c	yamir.moreno	IDA	One hybrid reporter system. Physical binding of the regulator to the regulated promoter proved by using electrophoretic mobility shift assay. . M. Guo, H. Feng et al. Dissecting transcription regulatory pathways through a new bacterial one-hybrid reporter system. Genome Res. 2009

TB Genome Annotation Portal