Abstract
This study investigates a mutant barnacle troponin C (TnC) protein (BTnC2-4-) in which the Ca2+binding sites (sites II and IV) have been rendered non-functional. Eliminating Ca2+ binding at both Ca2+-binding sites of barnacle TnC did not prevent the incorporation of BTnC2-4- into TnC- depleted myofibrillar bundles, although, as expected, the mutant was not able to effect muscle regulation. We conclude that the Mg2+ involved in stabilising the interaction between TnC and TnI in the barnacle must bind at a separate location to the Ca2+-binding sites. Competition experiments between BTnC2-4- and wild-type barnacle TnC (BTnCWT) or the native isoform BTnC2 indicate that BTnC2-4- has an approximately fourfold higher affinity for barnacle TnI than BTnCWT but a lower affinity for TnI compared to BTnC2. These results indicate that disabling sites II and IV changes the affinity of BTnC2-4- for TnC-denuded barnacle myofibrils, altering the stability of the bond formed between TnC and the thin filament.
| Original language | English |
|---|---|
| Pages (from-to) | 30-39 |
| Number of pages | 10 |
| Journal | Pflugers Archiv European Journal of Physiology |
| Volume | 438 |
| Issue number | 1 |
| DOIs | |
| State | Published - Jun 7 1999 |
| Externally published | Yes |
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Keywords
- Calcium
- Muscle
- Troponin C
ASJC Scopus subject areas
- Physiology
Cite this
Characterisation of a mutant of barnacle troponin C lacking Ca2+- binding sites at positions II and IV. / Allhouse, L. D.; Guzman, G.; Miller, T.; Li, Q.; Potter, J. D.; Ashley, C. C.
In: Pflugers Archiv European Journal of Physiology, Vol. 438, No. 1, 07.06.1999, p. 30-39.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Characterisation of a mutant of barnacle troponin C lacking Ca2+- binding sites at positions II and IV
AU - Allhouse, L. D.
AU - Guzman, G.
AU - Miller, T.
AU - Li, Q.
AU - Potter, J. D.
AU - Ashley, C. C.
PY - 1999/6/7
Y1 - 1999/6/7
N2 - This study investigates a mutant barnacle troponin C (TnC) protein (BTnC2-4-) in which the Ca2+binding sites (sites II and IV) have been rendered non-functional. Eliminating Ca2+ binding at both Ca2+-binding sites of barnacle TnC did not prevent the incorporation of BTnC2-4- into TnC- depleted myofibrillar bundles, although, as expected, the mutant was not able to effect muscle regulation. We conclude that the Mg2+ involved in stabilising the interaction between TnC and TnI in the barnacle must bind at a separate location to the Ca2+-binding sites. Competition experiments between BTnC2-4- and wild-type barnacle TnC (BTnCWT) or the native isoform BTnC2 indicate that BTnC2-4- has an approximately fourfold higher affinity for barnacle TnI than BTnCWT but a lower affinity for TnI compared to BTnC2. These results indicate that disabling sites II and IV changes the affinity of BTnC2-4- for TnC-denuded barnacle myofibrils, altering the stability of the bond formed between TnC and the thin filament.
AB - This study investigates a mutant barnacle troponin C (TnC) protein (BTnC2-4-) in which the Ca2+binding sites (sites II and IV) have been rendered non-functional. Eliminating Ca2+ binding at both Ca2+-binding sites of barnacle TnC did not prevent the incorporation of BTnC2-4- into TnC- depleted myofibrillar bundles, although, as expected, the mutant was not able to effect muscle regulation. We conclude that the Mg2+ involved in stabilising the interaction between TnC and TnI in the barnacle must bind at a separate location to the Ca2+-binding sites. Competition experiments between BTnC2-4- and wild-type barnacle TnC (BTnCWT) or the native isoform BTnC2 indicate that BTnC2-4- has an approximately fourfold higher affinity for barnacle TnI than BTnCWT but a lower affinity for TnI compared to BTnC2. These results indicate that disabling sites II and IV changes the affinity of BTnC2-4- for TnC-denuded barnacle myofibrils, altering the stability of the bond formed between TnC and the thin filament.
KW - Calcium
KW - Muscle
KW - Troponin C
UR - http://www.scopus.com/inward/record.url?scp=0033039893&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0033039893&partnerID=8YFLogxK
U2 - 10.1007/s004240050876
DO - 10.1007/s004240050876
M3 - Article
C2 - 10370084
AN - SCOPUS:0033039893
VL - 438
SP - 30
EP - 39
JO - Pflugers Archiv European Journal of Physiology
JF - Pflugers Archiv European Journal of Physiology
SN - 0031-6768
IS - 1
ER -