IspH–RPS1 and IspH–UbiA: “Rosetta stone” proteins

Rao, Guodong; O'Dowd, Bing; Li, Jikun; Wang, Ke; Oldfield, Eric

doi:10.1039/c5sc02600h

Cited by 5 publications

(16 citation statements)

References 59 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Both our and others sequence analyses suggest that this enzyme is a member of the UbiA superfamily of unknown function (Figure ) . It seems likely that many more enzymes, annotated as UbiA, exist that do not or are unlikely to possess 4‐hydroxybenzoate prenyltransferase activity ,…”

Section: Discussionmentioning

confidence: 51%

See 1 more Smart Citation

A Distinct Aromatic Prenyltransferase Associated with the Futalosine Pathway

et al. 2017

View full text Add to dashboard Cite

Menaquinone (MK) is an electron carrier molecule essential for respiration in most Gram positive bacteria. A crucial step in MK biosynthesis involves the prenylation of an aromatic molecule, catalyzed by integral membrane prenyltransferases of the UbiA (4‐hydroxybenzoate oligoprenyltransferase) superfamily. In the classical MK biosynthetic pathway, the prenyltransferase responsible is MenA (1,4‐dihydroxy‐2‐naphthoate octaprenyltransferase). Recently, an alternative pathway for formation of MK, the so‐called futalosine pathway, has been described in certain micro‐organisms. Until now, five soluble enzymes (MqnA‐MqnE) have been identified in the first steps. In this study, the genes annotated as ubiA from T. thermophilus and S. lividans were cloned, expressed and investigated for prenylation activity. The integral membrane proteins possess neither UbiA nor MenA activity and represent a distinct class of prenyltransferases associated with the futalosine pathway that we term MqnP. We identify a critical residue within a highly conserved Asp‐rich motif that serves to distinguish between members of the UbiA superfamily.

show abstract

Section: Discussionmentioning

confidence: 51%

“…[23] It seems likely that many more enzymes, annotated as UbiA, exist that do not or are unlikely to possess 4-hydroxybenzoate prenyltransferase activity. [17,45]…”

Section: Discussionmentioning

confidence: 99%

A Distinct Aromatic Prenyltransferase Associated with the Futalosine Pathway

et al. 2017

View full text Add to dashboard Cite

show abstract

“…The g ~5 signal is likely due to an S =7/2 species, as suggested previously. 17 The EPR results show, therefore, that there are clear differences between the Class A (AaIspH) and Class B (EcIspH) proteins. In the Class B protein EcIspH there are interactions between F302 and the 4Fe-4S cluster that result in changes in cluster structure, consistent with a role for this residue in ET and catalysis where, as can be seen in Table 1, the difference in k cat / K m between wild-type EcIspH and Ec302A is large.…”

Section: Resultsmentioning

confidence: 91%

“…However, since Fe 4 S 4 cluster incorporation into AaIspHs was less efficient than with EcIspH, we used the cluster reconstitution steps for AaIspHs that we described previously. 17 …”

Section: Methodsmentioning

confidence: 99%

“…In our group, we recently discovered that some IspHs from anaerobes form "Rosetta stone" hybrids with other proteins 17 and the IspH domains in these and many other obligate anaerobic bacteria lack the C-terminal tail region seen in EcIspH, suggesting that the presence of this region might be related to oxygen tolerance and indeed, IspH is one of the few essential proteins in E. coli that are air-sensitive. 18 Here, we sought to investigate the structure and function of a broad range of IspHs—proteins from anaerobic and aerobic bacteria, plants as well as parasitic protozoa—in order to see how different organisms might protect their clusters from oxidative damage, in addition to how residues on the ET side (as opposed to the substrate-binding side) of the protein might affect catalytic activity.…”

mentioning

confidence: 99%

See 1 more Smart Citation

Structure and Function of Four Classes of the 4Fe–4S Protein, IspH

Rao

Oldfield

2016

Biochemistry

Self Cite

View full text Add to dashboard Cite

IspH, E-1-hydroxy-2-methyl-but-2-enyl 4-diphosphate reductase, is an essential enzyme in isoprenoid biosynthesis and an important drug/herbicide target. Using X-ray crystallographic, bioinformatics, mutagenesis/kinetics/stability and EPR results we show that organisms from different environments ultilize one of four main IspH classes. The classes are based on the arrangement of the aromatic residues near the 4Fe-4S cluster and the presence or absence of N- and C-terminal extensions. They are: Class A, found primarily in anaerobic/microaerophilic bacteria; Class B, found in aerobic bacteria; Class C, found in cyanobacteria/plants; and Class D, found in apicomplexan parasites. Using mutagenesis, we show that the cluster-associated aromatic groups in Class A and a Class B IspHs enhance cluster oxidative stability. Y198A, F302A and a C-terminus truncation mutant of the Class B (E. coli) IspH have lower catalytic activity than wild-type protein when using methyl viologen as electron donor, but higher activity with dithionite as electron donor, due to ready access of the small reductant to the cluster, consistent with their increased oxygen/H2O2 sensitivity. F302A has the largest effect on the reaction rates and EPR studies indicate this residue affects Fe-S cluster structure. Similar effects on cluster stability are seen with Class A (F14A and Y98A) mutants, but effects on ET rates are smaller and there are no differences between the EPR spectra of mutant and wild-type proteins. Overall, the results are of general interest since they show, for the first time, that there are multiple IspH classes that have evolved to enable organisms to survive in diverse oxidative-stress environments.

show abstract