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Sequence and context dependence of EF-hand loop dynamics. An 15N relaxation study of a calcium-binding site mutant of calbindin D(9k)

Malmendal, Anders LU ; Carlström, Göran LU orcid ; Hambraeus, Charlotta ; Drakenberg, Torbjörn LU ; Forsén, Sture LU and Akke, Mikael LU orcid (1998) In Biochemistry 37(8). p.2586-2595
Abstract

The influence of amino acid sequence and structural context on the backbone dynamics of EF-hand calcium-binding loops was investigated using 15N spin relaxation measurements on the calcium-free state of the calbindin D(9k) mutant (A14D+A15Δ+P20Δ+N21G+P43M), in which the N-terminal pseudo- EF-hand loop, characteristic of S100 proteins, was engineered so as to conform with the C-terminal consensus EF-hand loop. The results were compared to a previous study of the apo state of the wild-type-like P43G calbindin D(9k) mutant. In the helical regions, the agreement with the P43G data is excellent, indicating that the structure and dynamics of the protein core are unaffected by the substitutions in the N-terminal loop. In the... (More)

The influence of amino acid sequence and structural context on the backbone dynamics of EF-hand calcium-binding loops was investigated using 15N spin relaxation measurements on the calcium-free state of the calbindin D(9k) mutant (A14D+A15Δ+P20Δ+N21G+P43M), in which the N-terminal pseudo- EF-hand loop, characteristic of S100 proteins, was engineered so as to conform with the C-terminal consensus EF-hand loop. The results were compared to a previous study of the apo state of the wild-type-like P43G calbindin D(9k) mutant. In the helical regions, the agreement with the P43G data is excellent, indicating that the structure and dynamics of the protein core are unaffected by the substitutions in the N-terminal loop. In the calcium- binding loops, the flexibility is drastically decreased compared to P43G, with the modified N-terminal loop showing a motional restriction comparable to that of the surrounding helixes. As in P43G, the motions in the C-terminal loop are less restricted than in the N-terminal loop. Differences in key hydrogen-bonding interactions correlate well with differences in dynamics and offer insights into the relationship between structure and dynamics of these EF-hand loops. It appears that the entire N-terminal EF-hand is built to form a rigid structure that allows calcium binding with only minor rearrangements and that the structural and dynamical properties of the entire EF-hand- rather than the loop sequence per se-is the major determinant of loop flexibility in this system.

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author
; ; ; ; and
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Biochemistry
volume
37
issue
8
pages
10 pages
publisher
The American Chemical Society (ACS)
external identifiers
  • scopus:0032562146
  • pmid:9485409
ISSN
0006-2960
DOI
10.1021/bi971798a
language
English
LU publication?
yes
id
32542116-d5a3-4f17-b097-a3fbc142841b
date added to LUP
2019-07-25 21:35:53
date last changed
2024-04-16 17:04:42
@article{32542116-d5a3-4f17-b097-a3fbc142841b,
  abstract     = {{<p>The influence of amino acid sequence and structural context on the backbone dynamics of EF-hand calcium-binding loops was investigated using <sup>15</sup>N spin relaxation measurements on the calcium-free state of the calbindin D(9k) mutant (A14D+A15Δ+P20Δ+N21G+P43M), in which the N-terminal pseudo- EF-hand loop, characteristic of S100 proteins, was engineered so as to conform with the C-terminal consensus EF-hand loop. The results were compared to a previous study of the apo state of the wild-type-like P43G calbindin D(9k) mutant. In the helical regions, the agreement with the P43G data is excellent, indicating that the structure and dynamics of the protein core are unaffected by the substitutions in the N-terminal loop. In the calcium- binding loops, the flexibility is drastically decreased compared to P43G, with the modified N-terminal loop showing a motional restriction comparable to that of the surrounding helixes. As in P43G, the motions in the C-terminal loop are less restricted than in the N-terminal loop. Differences in key hydrogen-bonding interactions correlate well with differences in dynamics and offer insights into the relationship between structure and dynamics of these EF-hand loops. It appears that the entire N-terminal EF-hand is built to form a rigid structure that allows calcium binding with only minor rearrangements and that the structural and dynamical properties of the entire EF-hand- rather than the loop sequence per se-is the major determinant of loop flexibility in this system.</p>}},
  author       = {{Malmendal, Anders and Carlström, Göran and Hambraeus, Charlotta and Drakenberg, Torbjörn and Forsén, Sture and Akke, Mikael}},
  issn         = {{0006-2960}},
  language     = {{eng}},
  month        = {{02}},
  number       = {{8}},
  pages        = {{2586--2595}},
  publisher    = {{The American Chemical Society (ACS)}},
  series       = {{Biochemistry}},
  title        = {{Sequence and context dependence of EF-hand loop dynamics. An <sup>15</sup>N relaxation study of a calcium-binding site mutant of calbindin D(9k)}},
  url          = {{http://dx.doi.org/10.1021/bi971798a}},
  doi          = {{10.1021/bi971798a}},
  volume       = {{37}},
  year         = {{1998}},
}