Table 3.

The ring-hydroxylating oxygenases for the catabolism of aromatic acids in E. coli

GeneLocation (min)aGene productSize in aa (kDa)Oxygenase protein familyNatural substrate(s)% Identity to other described proteinsc
hpaB 98.8Oxygenase component of HPA MOxb 520 (58.7)TC-FDMb 4HPA, 3HPA93 HpaA_Kp; 54 PheA_Btl; 48 PheA1_Btg
hpaC 98.8Reductase component of HPA MOx170 (18.6)TC-FDM4HPA, 3HPA80 HpaH_Kp; 26 SnaC_Sp; 25 ActVB_Sc; 22 PheA2_Btg; 21 StyB_P
mhpA 8.03HPP MOx554 (62.0)Monocomponent flavin MOx3HPP, 3HCI53 MhpA_Ct; 39 HppA_Rg; 27 TcmG_Sg; 22 OhpB_Rs; 22 PheA_Ps
hcaE 57.4Large terminal subunit of PP DOxb 453 (51.1)Class IIB DOxPP, CI48 TcbAa_Ps; 48 IpbA1_Re; 47 BphA1_Rs; 47 TodC1_Pp; 47 TecA1_Bs
hcaF 57.4Small terminal subunit of PP DOx172 (20.5)Class IIB DOxPP, CI38 BphE_Ct; 34 CumA2_Pf; 34 IpbA2_Ps
hcaC 57.4Ferredoxin subunit of PP DOx106 (11.3)Class IIB DOxPP, CI48 BphA3_Rs; 47 IpbA3_Re; 44 CumA3_Pf
hcaD 57.4Ferredoxin reductase subunit of PP DOx400 (43.9)Class IIB DOxPP, CI35 CmtAa_Pp; 31 IpbA4_Ps; 31 CumA4_Pf; 31 BphG_Ct; 30 TecA4_Bs
paaA 31.2Putative oxygenase of a diiron multicomponent oxygenased 309 (35.4)Diiron multicomponent oxygenased PA-CoA?d 64 PhaF_Pp
paaB 31.295 (10.9)63 PhaO_Pp
paaC 31.2248 (27.8)53 PhaG_Pp
paaD 31.2167 (18.6)33 PhaH_Pp
paaE 31.2Putative reductase of a diiron multicomponent oxygenase356 (39.3)Class IA-like reductasePA-CoA?41 PhaI_Pp; 30 TdnB_Pp; 28 TsaB_Ct; 27 Hcr_Ec; 26 Pdr_Bc
  • a The location of the genes is with respect to the E. coli K-12 genome. The location of thehpa genes (lacking in E. coli K-12) was inferred from the position of their flanking regions that are present in the chromosome of the K-12 strain.

  • b Abbreviations: MOx monooxygenase: DOx, dioxygenase; TC-FDM, two-component nonheme flavin-diffusible monooxygenase.

  • c The names of the proteins, with their GenBank accession numbers in parentheses, are as follows. HpaA_Kp and HpaH_Kp, oxygenase and reductase components of HPA MOx from Klebsiella pneumoniae (L41068); PheA_Btl, phenol MOx from Bacillus thermoleovorans (AF031325); PheA1_Btg and PheA2_Btg, oxygenase and reductase components of phenol MOx from B. thermoglucosidasius (AF140605); SnaC_Sp, flavin reductase in pristinamycin IIA biosynthesis from Streptomyces pristinaespiralis (P54994); ActVB_Sc, flavin reductase in biosynthesis of actinorhodin in S. coelicolor (X58833); StyB_P, reductase component of styrene MOx from Pseudomonasstrains (AJ000330, AF031161, Z92524); MhpA_Ct and HppA_Rg, 3HPP MOx from Comamonas testosteroni (AB024335) and Rhodococcus globerulus (U89712), respectively; TcmG_Sg, hydroxylase fromS. glaucescens (P39888); PheA_Ps, phenol MOx fromPseudomonas sp. strain EST1001 (P31020); OhpB_Rs, 2HPP MOx from Rhodococcus sp. strain V49 (AF274045); TcbAa_Ps, IpbA1_Re, BphA1_Rs, TodC1_Pp, and TecA1_Bs, large terminal subunits of the multicomponent DOx for degradation of chlorobenzene inPseudomonas sp. strain P51 (U15298), isopropylbenzene inR. erythropolis BD2 (U24277), biphenyl/polychlorobiphenyl (PCB) in Rhodococcus sp. strain RHA1 (D32142), toluene inP. putida F1 (J04996), and tetrachlorobenzene inBurkholderia sp. strain PS12 (U78099), respectivelyl; BphE_Ct, CumA2_Pf, and IpbA2_Ps, small terminal subunits of DOx for degradation of PCB in C. testosteroni B-356 (U47637,U47638), cumene in P. fluorescens IP01 (D37828), and isopropylbenzene in Pseudomonas sp. strain JR1 (U53507), respectively; BphA3_Rs, IpbA3_Re, and CumA3_Pf, ferredoxin subunits of multicomponent DOx for degradation of PCB in Rhodococcus sp. strain RHA1 (D32142), isopropylbenzene in R. erythropolisBD2 (U24277), and cumene in P. fluorescens IP01 (D37828), respectively; CmtAa_Pp, IpbA4_Ps, CumA4_Pf, BphG_Ct, and TecA4_Bs, ferredoxin reductase components of multicomponent DOx for degradation of p-cumate in P. putida F1 (U24215), isopropylbenzene in Pseudomonas sp. strain JR1 (U53507), cumene in P. fluorescens IP01 (D37828), PCB in C. testosteroni B-356 (U47637, U47638), and tetrachlorobenzene inBurkholderia sp. strain PS12 (U78099), respectively; PhaF, PhaO, PhaG, and PhaH, components of the putative PA-CoA oxygenase fromP. putida U (AF029714); Phal, putative reductase component of a PA-CoA oxygenase from P. putida U (AF029714); TdnB_Pp, TsaB_Ct, and Pdr_Bc, reductase components of aniline DOx from P. putida UCC22 (D85415), toluenesulfonate MOx from C. testosteroni T-2 (U32622), and phthalate Dox fromBurkholderia cepacia DBO1 (P33164), respectively; Hcr_Ec, reductase component of the hybrid cluster protein (prismane protein) from E. coli (P75824).

  • d Also for paaB, paaC, and paaD.