REGULATION OF IRON-SULFUR CLUSTER BIOGENESIS IN CYANOBACTERIA
Open Access
- Author:
- Wu, Yingxian
- Graduate Program:
- Biochemistry, Microbiology, and Molecular Biology
- Degree:
- Master of Science
- Document Type:
- Master Thesis
- Date of Defense:
- None
- Committee Members:
- Sprio Stefanou, Thesis Advisor/Co-Advisor
John H Golbeck, Thesis Advisor/Co-Advisor
Donald Ashley Bryant, Thesis Advisor/Co-Advisor - Keywords:
- cyanobacteria
Iron-sulfur cluster
SufR - Abstract:
- In this thesis, I present my studies on the two regulators for iron-sulfur cluster biogenesis in cyanobacteria, SYNPCC7002_A0128 and SufR. SYNPCC7002_A0128 is a homologue of IscR, the transcriptional regulator for iron-sulfur cluster biogenesis in Escherichia coli. To investigate the role of SYNPCC7002_A0128, a null-mutant strain of SYNPCC7002_A0128 was constructed in Synechococcus sp. PCC 7002. Physiological features were characterized and RT-PCR analyses were conducted for the mutant. The physiological features and the changes in the transcription profiles for the isc genes and the suf genes at the deletion of SYNPCC7002_A0128 revealed a regulatory role for SYNPCC7002_A0128 in iron-sulfur cluster biogenesis. SufR is found to be an iron-sulfur cluster containing, transcriptional regulator for the suf operon in cyanobacterium Synechocystis sp. PCC 6803. I continued the process of characterizing the [4Fe-4S]2+,1+ cluster in the SufR holo protein. Chemical analysis and spectroscopic analyses showed that SufR coordinated two [4Fe-4S]2+,1+ clusters per dimer. EPR spectroscopy revealed that reduced [4Fe-4S]2+,1+ cluster in SufR existed in a mixture of S = 1/2 and S = 3/2 ground spin states, with the S = 1/2 state accounting for 44% of the total spins. These results, combined with previous studies on the cysteine variants, suggested that there is one non-cysteine ligand that binds each [4Fe-4S]2+,1+ cluster in SufR