Gene/Protein
Disease
Symptom
Drug
Enzyme
Compound
Pivot Concepts:
Gene/Protein
Disease
Symptom
Drug
Enzyme
Compound
Target Concepts:
Gene/Protein
Disease
Symptom
Drug
Enzyme
Compound
Query: EC:3.6.3.1 (
Mg2+-ATPase
)
1,484
document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)
Recombinant
acidic calponin
, a member of the calponin family, interacted with F-actin, but not with microtubules, desmin filaments, tropomyosin, calmodulin, S100 and phosphatidylserine (PS) vesicles with significant affinity. The bindings of
acidic calponin
to F-actin occurred in a concentration-dependent manner and were saturated at a molar ratio of about 1
acidic calponin
to 1-2 actin molecules. The apparent Kd value of
acidic calponin
to F-actin was calculated to be 1.6 x 10(5) M(-1). Chemical cross-linking experiments indicated that a 1:1 molar covalent complex of
acidic calponin
and actin monomer was produced as in the case of basic calponinactin binding. No significant morphologic change of F-actin was observed by the addition of
acidic calponin
. Acidic calponin had little effect on actomyosin
Mg2+-ATPase
activity unlike basic calponin. Basic calponin partially competed with
acidic calponin
for binding to F-actin. Domain mapping with V8 protease revealed that
acidic calponin
binding site resided within the C-terminal 16 kDa fragment of actin, where the binding of basic calponin also occurs. However, both calponins showed reversal effects on fluorescence intensity of pyrene-labeled F-actin. Fragments of
acidic calponin
with 30 and 22 kDa, lacking the C-terminal acidic tail, were bound to F-actin. Interestingly, both the fragments became bound to PS vesicles, but not to other components. Circular dichroism studies showed that limited digestion of
acidic calponin
resulted in about 30% decrease of alpha-helix and beta contents. The present results suggest that
acidic calponin
is functionally distinct from basic calponin and expresses a novel characteristic after removal of the acidic tail region.
...
PMID:Functional analysis of rat acidic calponin. 1203 95
