Functional analysis of sequences adjacent to dapE of Corynebacterium glutamicum reveals the presence of aroP, which encodes the aromatic amino acid transporter

Wehrmann, Axel; Morakkabati, Schirin; Krämer, Reinhard; Sahm, Hermann; Eggeling, Lothar

doi:10.1128/jb.177.20.5991-5993.1995

Cited by 28 publications

(26 citation statements)

References 15 publications

(18 reference statements)

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“…A putative ABCtype transporter encoded by the ncgl1276, ncgl1277, and ncgl1278 genes and GluABCD for glutamate (23) had moderate sequence identities to HisJQMP of E. coli (9). An unknown-substrate APCtype transporter encoded by the ncgl0453 gene, PheP for phenylalanine (27), AroP for aromatic amino acids (28), and LysI for lysine (24) also showed moderate and variable sequence identities to AroP and HisP of S. Typhimurium and L. lactis, respectively (12,13).…”

Section: Resultsmentioning

confidence: 99%

“…AroP was identified as a general aromatic amino acid uptake system by gene disruption and complementation experiments (28). The kinetics of tyrosine uptake by AroP was further analyzed, and tyrosine uptake was competitively inhibited by tryptophan and phenylalanine (28). Besides AroP, another transporter (PheP) specific for phenylalanine uptake was also identified (27), confirming the presence of more than one uptake system for aromatic amino acids in C. glutamicum.…”

mentioning

confidence: 90%

“…Uptake of L-[ 14 C]histidine was determined with a rapid filtration assay as described previously (28). C. glutamicum cells were grown to mid-exponential phase, harvested, washed with 0.1 M Tris phosphate buffer (pH 6.8), and resuspended in the buffer.…”

Section: Methodsmentioning

confidence: 99%

“…Among them, GluABCD, LysI, BrnQ, MetQNI, MetPS, PheP, and AroP have been functionally characterized (23)(24)(25)(26)(27)(28). AroP was identified as a general aromatic amino acid uptake system by gene disruption and complementation experiments (28). The kinetics of tyrosine uptake by AroP was further analyzed, and tyrosine uptake was competitively inhibited by tryptophan and phenylalanine (28).…”

mentioning

confidence: 99%

“…The genome of C. glutamicum carries approximately 750 membrane proteins that could possibly function as transporters, and members of 17 transporter families are predicted to be involved in amino acid transport (1). Among them, GluABCD, LysI, BrnQ, MetQNI, MetPS, PheP, and AroP have been functionally characterized (23)(24)(25)(26)(27)(28). AroP was identified as a general aromatic amino acid uptake system by gene disruption and complementation experiments (28).…”

mentioning

confidence: 99%

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Characterization and Molecular Mechanism of AroP as an Aromatic Amino Acid and Histidine Transporter in Corynebacterium glutamicum

Shang

Zhang

et al. 2013

Journal of Bacteriology

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bCorynebacterium glutamicum is equipped with abundant membrane transporters to adapt to a changing environment. Many amino acid transporters have been identified in C. glutamicum, but histidine uptake has not been investigated in detail. Here, we identified the aromatic amino acid transporter encoded by aroP as a histidine transporter in C. glutamicum by a combination of the growth and histidine uptake features. Characterization of histidine uptake showed that AroP has a moderate affinity for histidine, with a K m value of 11.40 ؎ 2.03 M, and histidine uptake by AroP is competitively inhibited by the aromatic amino acids. Among the four substrates, AroP exhibits a stronger preference for tryptophan than for tyrosine, phenylalanine, and histidine. Homology structure modeling and molecular docking were performed to predict the substrate binding modes and conformational changes during substrate transport. These results suggested that tryptophan is best accommodated in the binding pocket due to shape compatibility, strong hydrophobic interactions, and the lowest binding energy, which is consistent with the observed substrate preference of AroP. Furthermore, the missense mutations of the putative substrate binding sites verified that Ser24, Ala28, and Gly29 play crucial roles in substrate binding and are highly conserved in the Gram-positive bacteria. Finally, the expression of aroP is not significantly affected by extracellular histidine or aromatic amino acids, indicating that the physiological role of AroP may be correlated with the increased fitness of C. glutamicum to assimilate extracellular amino acid for avoiding the high energy cost of amino acid biosynthesis.

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