The pH dependent spectral properties of Clostridium pasteurianum 2[Fe4S4] ferredoxin

摘要: Abstract The recently assigned 1 H NMR hyperfine signals of Clostridium pasteurianum ferredoxin were investigated over the pH range 8–12 to monitor possible pH-dependent conformational changes protein. For very high values minor perturbations detected in chemical shifts three β-CH 2 , cysteine protons cluster II, while I was not affected at all. These shift variations, which can be fitted a single p K ≈ 10.9, are interpreted as an effect deprotonation phenolic group Tyr-2, located reasonably close II. This hypothesis has been supported by means other techniques such CD and absorption spectroscopy that, on turn, able reveal spectral variations pH. Finally UV difference experiment provided further evidence for Tyr-2. influence Tyr-2 redox properties II is discussed.