Differential modulation of the active site environment of human carbonic anhydrase XII by cationic quantum dots and polylysine

Sumathra Manokaran, Xing Zhang, Wei Chen, D. K. Srivastava*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

8 Citations (Scopus)

Abstract

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.

Original languageEnglish
Pages (from-to)1376-1384
Number of pages9
JournalBiochimica et Biophysica Acta - Proteins and Proteomics
Volume1804
Issue number6
DOIs
Publication statusPublished - Jun 2010
Externally publishedYes

Keywords

  • Carbonic anhydrase XII
  • Dansylamide
  • Polylysine
  • Quantum dot

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