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pH-induced conformational changes in the soluble manganese-stabilizing protein of photosystem II.
| Content Provider | Semantic Scholar |
|---|---|
| Author | Weng, Jun Tan, Cuiyan Shen, Jian-Ren Yu, Yong Zhong Zeng, Xiaomei Xu, Chunhe Ruan, Kangcheng |
| Copyright Year | 2004 |
| Abstract | In this paper, we analyzed the pH-induced changes in the conformational states of the manganese-stabilizing protein (MSP) of photosystem II. Distinct conformational states of MSP were identified using fluorescence spectra, far-UV circular dichroism, and pressure-induced unfolding at varying suspension pH values, and four different conformational states of MSP were clearly distinguished using the center of fluorescence spectra mass when suspension pH was altered from 2 to 12. MSP was completely unfolded at a suspension pH above 11 and partly unfolded below a pH of 3. Analysis of the center of fluorescence spectral mass showed that the MSP structure appears stably folded around pH 6 and 4. The conformational state of MSP at pH 4 seems more stable than that at pH 6. Studies of peak positions of tryptophan fluorescence and MSP-bound 1-anilinonaphthalene-8-sulfonic acid fluorescence spectra supported this observation. A decrease in the suspension pH to 2 resulted in significant alterations in the MSP structure possibly because of protonation of unprotonated residues at lower pH, suggesting the existence of a large number of unprotonated amino acid residues at neutral pH possibly useful for proton transport in oxygen evolution. The acidic pH-induced conformational changes of MSP were reversible upon increase of pH to neutral pH; however, N-bromosuccinimide modification of tryptophan (Trp241) blocks the recovery of pH-induced conformational changes in MSP, implying that Trp241 is a key residue for the unfolded protein to form a functional structure. Thus, pH-induced structural changes of stable MSP (pH 6-4) may be utilized to analyze its functionality as a cofactor for oxygen evolution. |
| Starting Page | 627 |
| Ending Page | 635 |
| Page Count | 9 |
| File Format | PDF HTM / HTML |
| Alternate Webpage(s) | http://www.sibcb.ac.cn/publications/2004/2004-Biochemistry43-4855.pdf |
| PubMed reference number | 15096054v1 |
| Volume Number | 43 |
| Issue Number | 16 |
| Journal | Biochemistry |
| Language | English |
| Access Restriction | Open |
| Subject Keyword | 1-anilinonaphthalene-8-sulfonic acid Amino Acids Bromosuccinimide Circular Dichroism Fluorescence Oxygen Photosystem II Suspensions Thioctic Acid Tryptophan chemical cofactor proton transport |
| Content Type | Text |
| Resource Type | Article |
