TY - JOUR
T1 - Model peptide studies of sequence repeats derived from the intracrystalline biomineralization protein, SM50. II. Pro,Asn-rich tandem repeats
AU - Zhang, Bo
AU - Xu, Guangzhao
AU - Evans, John Spencer
PY - 2000/11
Y1 - 2000/11
N2 - In the biomineralization process, a number of Pro-rich proteins participate in the formation of three-dimensional supramolecular structures. One such protein superfamily, the Pro, Gly-rich sea urchin intracrystalline spicule matrix proteins, form protein-protein supramolecular assemblies that modify the microstructure of the inorganic mineral phase (calcite) within embryonic sea urchin spicules and adult sea urchin spines. These proteins represent a useful model for understanding Pro sequence usage and the resulting generation of extended or 'open' structures for protein-protein and/or protein-crystal recognition. In the sea urchin spicule matrix protein, SM50 (Strongylocentrotus purpuratus), there exists an unusual 20-residue Pro, Asn-containing repeat, - PNNPNNPNPNNPNNPNNPNP -, which links the upstream 15-residue C-terminal domain and the downstream 211-residue β-spiral repeat domain. To define the structural preferences of this 20-residue repeat, we created a 20-residue N- and C-terminal 'capped' peptidomimetic of this sequence. Using far-uv CD dichroism, CH(α) and α-15N conformational shifts, 3J(NH-CHα) coupling constants, sequential d(NN(i, i + I)) rotating frame nuclear Overhauser effect connectivities, d(αN(i, i + I))/d(NN(i, i + I)) intentsity ratios, amide temperature shift coefficients, amide solvent exchange, and simulated annealing refinement protocols, we have determined that this 20-residue repeat motif adopts an extended 'twist' structure consisting of turn- and coil-like regions. These findings are consistent with previous studies, which have shown that Pro-rich tandem repeats adopt extended, flexible structures in solution. We hypothesize that this 20-residue repeat may fulfill the role of a mineral-binding domain, a protein-protein docking domain, or as an internal 'molecular spacer' for the SM50 protein during spicule biocomposite formation. (C) 2000 John Wiley and Sons, Inc.
AB - In the biomineralization process, a number of Pro-rich proteins participate in the formation of three-dimensional supramolecular structures. One such protein superfamily, the Pro, Gly-rich sea urchin intracrystalline spicule matrix proteins, form protein-protein supramolecular assemblies that modify the microstructure of the inorganic mineral phase (calcite) within embryonic sea urchin spicules and adult sea urchin spines. These proteins represent a useful model for understanding Pro sequence usage and the resulting generation of extended or 'open' structures for protein-protein and/or protein-crystal recognition. In the sea urchin spicule matrix protein, SM50 (Strongylocentrotus purpuratus), there exists an unusual 20-residue Pro, Asn-containing repeat, - PNNPNNPNPNNPNNPNNPNP -, which links the upstream 15-residue C-terminal domain and the downstream 211-residue β-spiral repeat domain. To define the structural preferences of this 20-residue repeat, we created a 20-residue N- and C-terminal 'capped' peptidomimetic of this sequence. Using far-uv CD dichroism, CH(α) and α-15N conformational shifts, 3J(NH-CHα) coupling constants, sequential d(NN(i, i + I)) rotating frame nuclear Overhauser effect connectivities, d(αN(i, i + I))/d(NN(i, i + I)) intentsity ratios, amide temperature shift coefficients, amide solvent exchange, and simulated annealing refinement protocols, we have determined that this 20-residue repeat motif adopts an extended 'twist' structure consisting of turn- and coil-like regions. These findings are consistent with previous studies, which have shown that Pro-rich tandem repeats adopt extended, flexible structures in solution. We hypothesize that this 20-residue repeat may fulfill the role of a mineral-binding domain, a protein-protein docking domain, or as an internal 'molecular spacer' for the SM50 protein during spicule biocomposite formation. (C) 2000 John Wiley and Sons, Inc.
KW - Biomineralization
KW - Proline repeats
KW - Sea urchin embryo
KW - Sea urchine spicule
KW - Self-assembly
KW - nmr
UR - http://www.scopus.com/inward/record.url?scp=0034327881&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0034327881&partnerID=8YFLogxK
U2 - 10.1002/1097-0282(200011)54:6<464::AID-BIP90>3.0.CO;2-N
DO - 10.1002/1097-0282(200011)54:6<464::AID-BIP90>3.0.CO;2-N
M3 - Article
C2 - 10951331
AN - SCOPUS:0034327881
SN - 0006-3525
VL - 54
SP - 464
EP - 475
JO - Biopolymers
JF - Biopolymers
IS - 6
ER -