F
IPR044643

N-(5'-phosphoribosyl)anthranilate isomerase family

InterPro entry
Short nameTrpF_fam
Overlapping
homologous
superfamilies
 

Description

N-(5'-phosphoribosyl) anthranilate isomerase (PRAI) is an enzyme that catalyses the third step of tryptophan biosynthesis.

Phosphoribosylanthranilate isomerase is monomeric and labile in most mesophilic microorganisms, but dimeric and stable in the hyperthermophile Thermotoga maritima (tPRAI)
[2]
. The comparison to the known 2.0 A structure of PRAI from Escherichia coli (ePRAI) shows that tPRAI has the complete TIM- or (β/α)8-barrel fold, whereas helix α5 in ePRAI is replaced by a loop. The subunits of tPRAI associate via the N-terminal faces of their central β-barrels. Two long, symmetry-related loops that protrude reciprocally into cavities of the other subunit provide for multiple hydrophobic interactions. Moreover, the side chains of the N-terminal methionines and the C-terminal leucines of both subunits are immobilized in a hydrophobic cluster, and the number of salt bridges is increased in tPRAI. These features appear to be mainly responsible for the high thermostability of tPRAI
[1]
.

References

1.Crystal structure at 2.0 A resolution of phosphoribosyl anthranilate isomerase from the hyperthermophile Thermotoga maritima: possible determinants of protein stability. Hennig M, Sterner R, Kirschner K, Jansonius JN. Biochemistry 36, 6009-16, (1997). View articlePMID: 9166771

2.Structure and function of mutationally generated monomers of dimeric phosphoribosylanthranilate isomerase from Thermotoga maritima. Thoma R, Hennig M, Sterner R, Kirschner K. Structure 8, 265-76, (2000). View articlePMID: 10745009

GO terms

Cross References

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