Susceptibility Test of Two Ca2+-ATPase Conformers to Denaturants and Polyols to Outline Their Structural Difference

Susceptibility Test of Two Ca2+-ATPase Conformers to Denaturants and Polyols to Outline Their... To determine the effect of denaturants [guanidine hydrochloride (GdnHCl) and urea] and polyols [with various molecular masses (62.1–600)] on calcium binding at the two hypothesized conformers (A and B forms) of the chemically equivalent sarcoplasmic reticulum Ca2+-ATPase, which bind two calcium ions in different manners, we examined the effect of these reagents on the calcium dependence of ATP-supported phosphorylation of the ATPase molecules and of their calcium-activated, acetyl phosphatate hydrolytic activity. (1) GdnHCl (~0.05 M) and urea (~0.5 M) increased the apparent calcium affinity (K 0.5) of 2–6 μM of noncooperative binding [Hill coefficient (n H) ~ 1] of the A form to 10–40 μM. (2) The employed polyols transformed the binding of the A form into cooperative binding (n H ~ 2), accompanying the approach of its K 0.5 value to that (K 0.5 = 0.04–0.2 μM) of the cooperative binding (n H ~ 2) of the B form; the transition concentration (0.025–2 M) of the polyols, above which such transformation occurs, was in inverse relation to their molecular mass. (3) The binding of the B form was resistant to these denaturants and polyols. Based on these data, a structural model of the two forms, calcium-binding domains of which are loosely and compactly folded, is presented. http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png The Journal of Membrane Biology Springer Journals

Susceptibility Test of Two Ca2+-ATPase Conformers to Denaturants and Polyols to Outline Their Structural Difference

Loading next page...
 
/lp/springer_journal/susceptibility-test-of-two-ca2-atpase-conformers-to-denaturants-and-HlujKJWI11
Publisher
Springer-Verlag
Copyright
Copyright © 2012 by Springer Science+Business Media New York
Subject
Life Sciences; Biochemistry, general; Human Physiology
ISSN
0022-2631
eISSN
1432-1424
D.O.I.
10.1007/s00232-012-9513-8
Publisher site
See Article on Publisher Site

Abstract

To determine the effect of denaturants [guanidine hydrochloride (GdnHCl) and urea] and polyols [with various molecular masses (62.1–600)] on calcium binding at the two hypothesized conformers (A and B forms) of the chemically equivalent sarcoplasmic reticulum Ca2+-ATPase, which bind two calcium ions in different manners, we examined the effect of these reagents on the calcium dependence of ATP-supported phosphorylation of the ATPase molecules and of their calcium-activated, acetyl phosphatate hydrolytic activity. (1) GdnHCl (~0.05 M) and urea (~0.5 M) increased the apparent calcium affinity (K 0.5) of 2–6 μM of noncooperative binding [Hill coefficient (n H) ~ 1] of the A form to 10–40 μM. (2) The employed polyols transformed the binding of the A form into cooperative binding (n H ~ 2), accompanying the approach of its K 0.5 value to that (K 0.5 = 0.04–0.2 μM) of the cooperative binding (n H ~ 2) of the B form; the transition concentration (0.025–2 M) of the polyols, above which such transformation occurs, was in inverse relation to their molecular mass. (3) The binding of the B form was resistant to these denaturants and polyols. Based on these data, a structural model of the two forms, calcium-binding domains of which are loosely and compactly folded, is presented.

Journal

The Journal of Membrane BiologySpringer Journals

Published: Nov 3, 2012

References

You’re reading a free preview. Subscribe to read the entire article.


DeepDyve is your
personal research library

It’s your single place to instantly
discover and read the research
that matters to you.

Enjoy affordable access to
over 18 million articles from more than
15,000 peer-reviewed journals.

All for just $49/month

Explore the DeepDyve Library

Search

Query the DeepDyve database, plus search all of PubMed and Google Scholar seamlessly

Organize

Save any article or search result from DeepDyve, PubMed, and Google Scholar... all in one place.

Access

Get unlimited, online access to over 18 million full-text articles from more than 15,000 scientific journals.

Your journals are on DeepDyve

Read from thousands of the leading scholarly journals from SpringerNature, Elsevier, Wiley-Blackwell, Oxford University Press and more.

All the latest content is available, no embargo periods.

See the journals in your area

DeepDyve

Freelancer

DeepDyve

Pro

Price

FREE

$49/month
$360/year

Save searches from
Google Scholar,
PubMed

Create lists to
organize your research

Export lists, citations

Read DeepDyve articles

Abstract access only

Unlimited access to over
18 million full-text articles

Print

20 pages / month

PDF Discount

20% off