TY - JOUR
T1 - Differential modulation of the active site environment of human carbonic anhydrase XII by cationic quantum dots and polylysine
AU - Manokaran, Sumathra
AU - Zhang, Xing
AU - Chen, Wei
AU - Srivastava, D. K.
PY - 2010/6
Y1 - 2010/6
N2 - Due to prevalence of negative charges on the protein surface, opposite to the active site pocket of human carbonic anhydrase XII (hCA XII), both positively charged CdTe quantum dots (Qds+) and polylysine electrostatically interact with the enzyme, and such interaction does not influence the catalytic activity of the enzyme. However, both these cationic macromolecules differently modulate the active site environment of the enzyme. The steady-state kinetic data revealed that whereas polylysine exhibited no influence on dansylamide (DNSA) dependent inhibition of the enzyme, Qds+ overcame such an inhibitory effect, leading to almost 70% restoration of the catalytic activity of the enzyme. We provide evidence that DNSA remains bound to the enzyme upon interaction with both polylysine and Qds+. Arguments are presented that the above differential feature of polylysine and Qds+ on hCA XII is encoded in the "rigidity" versus "flexibility" of these cationic macromolecules.
AB - Due to prevalence of negative charges on the protein surface, opposite to the active site pocket of human carbonic anhydrase XII (hCA XII), both positively charged CdTe quantum dots (Qds+) and polylysine electrostatically interact with the enzyme, and such interaction does not influence the catalytic activity of the enzyme. However, both these cationic macromolecules differently modulate the active site environment of the enzyme. The steady-state kinetic data revealed that whereas polylysine exhibited no influence on dansylamide (DNSA) dependent inhibition of the enzyme, Qds+ overcame such an inhibitory effect, leading to almost 70% restoration of the catalytic activity of the enzyme. We provide evidence that DNSA remains bound to the enzyme upon interaction with both polylysine and Qds+. Arguments are presented that the above differential feature of polylysine and Qds+ on hCA XII is encoded in the "rigidity" versus "flexibility" of these cationic macromolecules.
KW - Carbonic anhydrase XII
KW - Dansylamide
KW - Polylysine
KW - Quantum dot
UR - http://www.scopus.com/inward/record.url?scp=77949912302&partnerID=8YFLogxK
U2 - 10.1016/j.bbapap.2010.02.014
DO - 10.1016/j.bbapap.2010.02.014
M3 - Article
C2 - 20215053
AN - SCOPUS:77949912302
SN - 1570-9639
VL - 1804
SP - 1376
EP - 1384
JO - Biochimica et Biophysica Acta - Proteins and Proteomics
JF - Biochimica et Biophysica Acta - Proteins and Proteomics
IS - 6
ER -