TY - JOUR
T1 - In vitro effects of recombinant otoconin 90 upon calcite crystal growth. Significance of tertiary structure
AU - Lu, Wenfu
AU - Zhou, Dan
AU - Freeman, John J.
AU - Thalmann, Isolde
AU - Ornitz, David M.
AU - Thalmann, Ruediger
N1 - Funding Information:
We thank Dr. Lijuan Zhang for prediction of the chondroitin sulfate site; Dr. Jianbo Wang for providing the mammalian expression vector pcDNA3.1 (+) neomycin; Dr. Carl Frieden for valuable discussion on CD; Dr. Thomas Brett for technical assistance with CD and DLS, and discussion of DLS data. This study was supported by DC 009320 (RT) and DC02236 (DMO) from the National Institute on Deafness and other Communication Disorders, NIH .
PY - 2010/9
Y1 - 2010/9
N2 - Otoconia are biomineral particles of microscopic size essential for perception of gravity and maintenance of balance. Millions of older Americans are affected in their mobility, quality of life and in their health by progressive demineralization of otoconia. Currently, no effective means to prevent or counteract this process are available. Because of prohibitive anatomical and biological constraints, otoconial research is lagging far behind other systems such as bone and teeth. We have overcome these obstacles by generating otoconial matrix proteins by recombinant techniques. In the present study, we evaluated the effects of recombinant Otoconin 90 (OC90), the principal soluble matrix protein upon calcite crystal growth patterns in vitro. Our findings highlight multiple effects, including facilitation of nucleation, and inhibition of crystal growth in a concentration-dependent manner. Moreover, OC90 induces morphologic changes characteristic of native otoconia.OC90 is considerably less acidic than the prototypical invertebrate CaCO3 -associated protein, but is nevertheless an effective modulator of calcite crystal growth. Based on homology modeling of the sPLA2-like domains of OC90, we propose that the lower density of acidic residues of the primary sequence is compensated by formation of major anionic surface clusters upon folding into tertiary conformation.
AB - Otoconia are biomineral particles of microscopic size essential for perception of gravity and maintenance of balance. Millions of older Americans are affected in their mobility, quality of life and in their health by progressive demineralization of otoconia. Currently, no effective means to prevent or counteract this process are available. Because of prohibitive anatomical and biological constraints, otoconial research is lagging far behind other systems such as bone and teeth. We have overcome these obstacles by generating otoconial matrix proteins by recombinant techniques. In the present study, we evaluated the effects of recombinant Otoconin 90 (OC90), the principal soluble matrix protein upon calcite crystal growth patterns in vitro. Our findings highlight multiple effects, including facilitation of nucleation, and inhibition of crystal growth in a concentration-dependent manner. Moreover, OC90 induces morphologic changes characteristic of native otoconia.OC90 is considerably less acidic than the prototypical invertebrate CaCO3 -associated protein, but is nevertheless an effective modulator of calcite crystal growth. Based on homology modeling of the sPLA2-like domains of OC90, we propose that the lower density of acidic residues of the primary sequence is compensated by formation of major anionic surface clusters upon folding into tertiary conformation.
UR - http://www.scopus.com/inward/record.url?scp=77955846176&partnerID=8YFLogxK
U2 - 10.1016/j.heares.2010.05.019
DO - 10.1016/j.heares.2010.05.019
M3 - Article
C2 - 20595020
AN - SCOPUS:77955846176
VL - 268
SP - 172
EP - 183
JO - Hearing Research
JF - Hearing Research
SN - 0378-5955
IS - 1-2
ER -