Sodium-23 and lanthanum-139 nuclear magnetic resonance studies of cation binding to aqualysin I, a thermostable serine protease.
Aqualysin I has at least two Ca2+-binding sites that have different affinities for Ca2+. The binding of various metal ions to aqualysin I was studied using 23Na- and 139La-NMR spectrometry. Evidence is presented that Ca2+, La3+, and Na+ bind to the low-affinity Ca2+-binding site of aqualysin I, but Mg2+ does not. Our results confirm that binding of metals at the low-affinity Ca2+-binding site is essential for thermostabilization, since the addition of Mg2+ did not result in thermostabilization. La3+ was found to bind to both the low-affinity Ca2+-binding site and an additional metal ion-binding site that can also be involved in the thermostabilization of aqualysin I.
Suefuji
Kyoko
K
Department of Biotechnology, The University of Tokyo, Japan.
Lin
Shie-Jea
SJ
Wakagi
Takayoshi
T
Matsuzawa
Hiroshi
H
Yoshimura
Etsuro
E
D001665:Binding Sites; D002118:Calcium / Q000737:chemistry / Q000378:metabolism; D002412:Cations / Q000737:chemistry / Q000378:metabolism; D004795:Enzyme Stability; D020035:Holoenzymes / Q000737:chemistry / Q000378:metabolism; D007811:Lanthanum / Q000737:chemistry / Q000378:metabolism; D008274:Magnesium / Q000737:chemistry / Q000378:metabolism; D009682:Magnetic Resonance Spectroscopy; D008670:Metals / Q000737:chemistry* / Q000378:metabolism*; D011485:Protein Binding; D012697:Serine Endopeptidases / Q000737:chemistry* / Q000378:metabolism*; D012964:Sodium / Q000737:chemistry / Q000378:metabolism; D013696:Temperature
D002412:Cations; D020035:Holoenzymes; D008670:Metals; D007811:Lanthanum; D012964:Sodium; D012697:Serine Endopeptidases; C055102:aqualysin I; D008274:Magnesium; D002118:Calcium