Comparison of the Ca2+-binding Properties of Human Recombinant Calretinin-22k and Calretinin

Abstract

Calretinin-22k (CR-22k. Together, our data suggest the presence of an allosteric conformational unit encompassing sites I-III for CR-22k and I-IV for CR, with a very similar conformation and conformational changes for both proteins. In the allosteric unit of CR, site IV is fully active, whereas in CR-22k this site has a 80-fold decreased affinity, due to the decreased amphiphilic properties of the C-terminal helix of this site. Some very specific Ca 2؉ -dependent conformational changes suggest that both CR and CR-22k belong to the "sensor"-type family of Ca 2؉ -binding proteins.

Two Forms of the Apoptosis-linked Protein ALG-2 with Different Ca2+ Affinities and Target Recognition

“…27 are summarized in Table I. Ca 2ϩ binding or dissociation only slightly modify the secondary structure of both ALG-2 isoforms, a feature also observed in several other Ca 2ϩ -binding proteins, such as calretinin (30) or S100 proteins (31).…”

Binding of calcium ions and SNAP-25 to the hexa EF-hand protein secretagogin

“…An investigation of the possible role of secretagogin in exocytosis is an important question for the future. [43]. The differences in Ca 2+ affinities probably reflect important biological and evolutionary differences between these proteins.…”

Reliability and Heterogeneity of Calcium Signaling at Single Presynaptic Boutons of Cerebellar Granule Cells

“…Prominent calcium binding proteins such as the kinetically slow parvalbumin (Lee et al, 2000) and calbindin are not expressed in granule cells (Bastianelli, 2003). It is likely that calretinin, a calcium binding protein with rapid kinetics (Schwaller et al, 1997) that is expressed in granule cells, makes a prominent contribution to the endogenous buffer capacity (Bastianelli, 2003;Gall et al, 2005).…”