TY - JOUR
T1 - Photochemically induced dynamic nuclear polarisation NMR study of the aromatic residues of sea‐anemone polypeptide cardiac stimulants
AU - NORTON, Raymond S.
AU - BERESS, Laszlo
AU - STOB, Sijtze
AU - BOELENS, Rolf
AU - KAPTEIN, Robert
PY - 1986
Y1 - 1986
N2 - One‐dimensional and two‐dimensional photochemically induced dynamic nuclear polarisation (photo‐CIDNP) nuclear magnetic resonance spectra have been recorded for the sea‐anemone polypeptide cardiac stimulants anthopleurin‐A and Anemonia sulcata toxins I and II. In anthopleurin‐A and toxin II, all three Trp residues are accessible to the flavin dye, although Trp‐23 in anthopleurin‐A shows a weaker photo‐CIDNP response than Trp‐33 and Trp‐45. Tyr‐25 in anthopleurin‐A also shows a strong response. In toxin I, Trp‐23, Trp‐33 and Tyr‐45 (which replaces Trp in this molecule) are accessible to the dye. The pH dependences of the photo‐CIDNP spectra of all three polypeptides have been examined. The response of Trp‐33 increases significantly with pH. The two His residues of anthopleurin‐A and toxin II display a response in their imidazole forms, but not their imidazolium forms. The surface accessibilities of Trp‐23 and Trp‐33 are discussed in relation to the interaction of these polypeptides with the Na+ channel.
AB - One‐dimensional and two‐dimensional photochemically induced dynamic nuclear polarisation (photo‐CIDNP) nuclear magnetic resonance spectra have been recorded for the sea‐anemone polypeptide cardiac stimulants anthopleurin‐A and Anemonia sulcata toxins I and II. In anthopleurin‐A and toxin II, all three Trp residues are accessible to the flavin dye, although Trp‐23 in anthopleurin‐A shows a weaker photo‐CIDNP response than Trp‐33 and Trp‐45. Tyr‐25 in anthopleurin‐A also shows a strong response. In toxin I, Trp‐23, Trp‐33 and Tyr‐45 (which replaces Trp in this molecule) are accessible to the dye. The pH dependences of the photo‐CIDNP spectra of all three polypeptides have been examined. The response of Trp‐33 increases significantly with pH. The two His residues of anthopleurin‐A and toxin II display a response in their imidazole forms, but not their imidazolium forms. The surface accessibilities of Trp‐23 and Trp‐33 are discussed in relation to the interaction of these polypeptides with the Na+ channel.
UR - http://www.scopus.com/inward/record.url?scp=0022542862&partnerID=8YFLogxK
U2 - 10.1111/j.1432-1033.1986.tb09674.x
DO - 10.1111/j.1432-1033.1986.tb09674.x
M3 - Article
C2 - 2872052
AN - SCOPUS:0022542862
SN - 0014-2956
VL - 157
SP - 343
EP - 346
JO - European Journal of Biochemistry
JF - European Journal of Biochemistry
IS - 2
ER -