Title

Analysis of the Cysteine Desulfurase Mechanism Used by the PLP Bound Protein SufS

School Name

South Carolina Governor's School for Science & Mathematics

Grade Level

12th Grade

Presentation Topic

Biochemistry

Presentation Type

Mentored

Oral Presentation Award

3rd Place

Abstract

Iron homeostasis is crucial to overall cellular health. To keep iron levels in the cell stable, organisms have developed methods to regulate iron due to its toxicity at high concentrations. One of these is the creation of iron – sulfur (Fe – S) clusters. In E. coli, the Suf Pathway contributes to the biogenesis of these clusters. The Suf pathway is primarily used under oxidative stress, which is when the cell has an elevated concentration of hydrogen peroxide, or under conditions of iron starvation. The key proteins of the Suf pathway targeted in this research are SufS and SufE. SufS functions in conjunction with SufE to catalyze the removal of sulfur from L – Cysteine to create a “protein bound persulfide.” Studying these two proteins gives greater insight to the effectiveness and role of the Suf pathway in E. coli cells. The removal of sulfur from L – Cysteine is dependent on pyridoxal 5’– phosphate (PLP), a coenzyme that is bound to SufS. To determine the amount of PLP bound per SufS monomer, a PLP quantification was run, with the PLP concentration being approximately equal to the SufS concentration. A Cysteine – Desulfurase Assay was used to test the desulfurase activity of SufS in the presence and absence of SufE. It was found that SufS and SufE had greater desulfurase activity when compared with SufS alone. Finally, stopped-flow spectroscopy was used to analyze the kinetics of the SufS cysteine desulfurase activity.

Location

Founders Hall 111 A

Start Date

3-30-2019 11:15 AM

Presentation Format

Oral Only

Group Project

No

COinS
 
Mar 30th, 11:15 AM

Analysis of the Cysteine Desulfurase Mechanism Used by the PLP Bound Protein SufS

Founders Hall 111 A

Iron homeostasis is crucial to overall cellular health. To keep iron levels in the cell stable, organisms have developed methods to regulate iron due to its toxicity at high concentrations. One of these is the creation of iron – sulfur (Fe – S) clusters. In E. coli, the Suf Pathway contributes to the biogenesis of these clusters. The Suf pathway is primarily used under oxidative stress, which is when the cell has an elevated concentration of hydrogen peroxide, or under conditions of iron starvation. The key proteins of the Suf pathway targeted in this research are SufS and SufE. SufS functions in conjunction with SufE to catalyze the removal of sulfur from L – Cysteine to create a “protein bound persulfide.” Studying these two proteins gives greater insight to the effectiveness and role of the Suf pathway in E. coli cells. The removal of sulfur from L – Cysteine is dependent on pyridoxal 5’– phosphate (PLP), a coenzyme that is bound to SufS. To determine the amount of PLP bound per SufS monomer, a PLP quantification was run, with the PLP concentration being approximately equal to the SufS concentration. A Cysteine – Desulfurase Assay was used to test the desulfurase activity of SufS in the presence and absence of SufE. It was found that SufS and SufE had greater desulfurase activity when compared with SufS alone. Finally, stopped-flow spectroscopy was used to analyze the kinetics of the SufS cysteine desulfurase activity.