4P06

Bacterial arylsulfate sulfotransferase (ASST) H436N mutant with 4-methylumbelliferyl sulfate (MUS) in the active site

Summary for 4P06

• Entry DOI: 10.2210/pdb4p06/pdb
• Related: 3ELQ 3ETS 3ETT 4P04 4P05 4P07
• Descriptor: Arylsulfate sulfotransferase AssT, SULFATE ION, (4-methyl-2-oxidanylidene-chromen-7-yl) hydrogen sulfate, ... (4 entities in total)
• Functional Keywords: sulfotransferase, beta propeller, active site mutant, transferase
• Biological source: Escherichia coli CFT073
• Total number of polymer chains: 2
• Total formula weight: 128445.84

Authors

Malojcic, G.,Owen, R.L.,Glockshuber, R. (deposition date: 2014-02-20, release date: 2014-03-26, Last modification date: 2024-11-13)

Primary citation

Malojcic, G.,Owen, R.L.,Glockshuber, R.
Structural and mechanistic insights into the PAPS-independent sulfotransfer catalyzed by bacterial aryl sulfotransferase and the role of the DsbL/Dsbl system in its folding.
Biochemistry, 53:1870-1877, 2014

PubMed Abstract: Bacterial aryl sulfotransferases (ASSTs) catalyze sulfotransfer from a phenolic sulfate to a phenol. These enzymes are frequently found in pathogens and upregulated during infection. Their mechanistic understanding is very limited, and their natural substrates are unknown. Here, the crystal structures of Escherichia coli CFT073 ASST trapped in its presulfurylation state with model donor substrates bound in the active site are reported, which reveal the molecular interactions governing substrate recognition. Furthermore, spectroscopic titrations with donor substrates and sulfurylation kinetics of ASST illustrate that this enzyme binds substrates in a 1:1 stoichiometry and that the active sites of the ASST homooligomer act independently. Mass spectrometry and crystallographic experiments of ASST incubated with human urine demonstrate that urine contains a sulfuryl donor substrate. In addition, we examined the capability of the two paralogous dithiol oxidases present in uropathogenic E. coli CFT073, DsbA, and the ASST-specific enzyme DsbL, to introduce the single, conserved disulfide bond into ASST. We show that DsbA and DsbL introduce the disulfide bond into unfolded ASST at similar rates. Hence, a chaperone effect of DsbL, not present in DsbA, appears to be responsible for the dependence of efficient ASST folding on DsbL in vivo. The conservation of paralogous dithiol oxidases with different substrate specificities in certain bacterial strains may therefore be a consequence of the complex folding pathways of their substrate proteins.

PubMed: 24601529
DOI: 10.1021/bi401725j

Experimental method

X-RAY DIFFRACTION (2.1 Å)