Calcium Ion Binding to Pancreatic Phospholipase A2 and Its Zymogen : A 43Ca NMR Study
(1984) In Biochemistry 23(11). p.2387-2392- Abstract
Calcium ion binding to phospholipase A2 and its zymogen has been studied by 43Ca NMR. The temperature dependence of the band shape of the calcium-43 NMR signal has been used to calculate the calcium ion exchange rate. The on-rate was calculated to be 5 × 106 M-1 s-1, which is 2 orders of magnitude less than the diffusion limit of the hydrated Ca2+ ion in water. The 43Ca quadrupole coupling constant for calcium ions bound to phospholipase, χ = 1.4 MHz, is significantly larger than those found for EF-hand proteins, indicating a less symmetric site. For prophospholipase A2, we found χ = 0.8 MHz, indicating a calcium binding site, which is somewhat more symmetric than the EF-hand sites. The dependence of the... (More)
Calcium ion binding to phospholipase A2 and its zymogen has been studied by 43Ca NMR. The temperature dependence of the band shape of the calcium-43 NMR signal has been used to calculate the calcium ion exchange rate. The on-rate was calculated to be 5 × 106 M-1 s-1, which is 2 orders of magnitude less than the diffusion limit of the hydrated Ca2+ ion in water. The 43Ca quadrupole coupling constant for calcium ions bound to phospholipase, χ = 1.4 MHz, is significantly larger than those found for EF-hand proteins, indicating a less symmetric site. For prophospholipase A2, we found χ = 0.8 MHz, indicating a calcium binding site, which is somewhat more symmetric than the EF-hand sites. The dependence of the Ca NMR band shape on the calcium ion concentration showed that there are two cation binding sites on the phospholipase A2 molecule: K1 = 4 × 103 M-1 and K2 = 20 M. The strong site was found to be affected by a pKa = 6.5 and the weak site by pKa = 4.5.
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- author
- Drakenberg, Torbjörn LU ; Andersson, Thomas ; Forsén, Sture and Wieloch, Tadeusz LU
- organization
- publishing date
- 1984-01-01
- type
- Contribution to journal
- publication status
- published
- subject
- in
- Biochemistry
- volume
- 23
- issue
- 11
- pages
- 6 pages
- publisher
- The American Chemical Society (ACS)
- external identifiers
-
- scopus:0021235854
- pmid:6477872
- ISSN
- 0006-2960
- DOI
- 10.1021/bi00306a011
- language
- English
- LU publication?
- yes
- id
- be0bee56-57bf-471e-9a66-9dc56f34fbb9
- date added to LUP
- 2019-06-13 17:26:28
- date last changed
- 2024-04-02 07:54:43
@article{be0bee56-57bf-471e-9a66-9dc56f34fbb9,
abstract = {{<p>Calcium ion binding to phospholipase A2 and its zymogen has been studied by 43Ca NMR. The temperature dependence of the band shape of the calcium-43 NMR signal has been used to calculate the calcium ion exchange rate. The on-rate was calculated to be 5 × 106 M<sub>-1</sub> s<sub>-1</sub>, which is 2 orders of magnitude less than the diffusion limit of the hydrated Ca<sub>2+</sub> ion in water. The 43Ca quadrupole coupling constant for calcium ions bound to phospholipase, χ = 1.4 MHz, is significantly larger than those found for EF-hand proteins, indicating a less symmetric site. For prophospholipase A2, we found χ = 0.8 MHz, indicating a calcium binding site, which is somewhat more symmetric than the EF-hand sites. The dependence of the Ca NMR band shape on the calcium ion concentration showed that there are two cation binding sites on the phospholipase A2 molecule: K1 = 4 × 103 M<sup>-1</sup> and K2 = 20 M. The strong site was found to be affected by a pKa = 6.5 and the weak site by pKa = 4.5.</p>}},
author = {{Drakenberg, Torbjörn and Andersson, Thomas and Forsén, Sture and Wieloch, Tadeusz}},
issn = {{0006-2960}},
language = {{eng}},
month = {{01}},
number = {{11}},
pages = {{2387--2392}},
publisher = {{The American Chemical Society (ACS)}},
series = {{Biochemistry}},
title = {{Calcium Ion Binding to Pancreatic Phospholipase A<sub>2</sub> and Its Zymogen : A <sup>43</sup>Ca NMR Study}},
url = {{http://dx.doi.org/10.1021/bi00306a011}},
doi = {{10.1021/bi00306a011}},
volume = {{23}},
year = {{1984}},
}