Carbonic anhydrase I is recognized by an SOD1 antibody upon biotinylation of human spinal cord extracts

Document Type

Article

Abstract

We recently reported the presence of a novel 32 kDa protein immunoreactive to a copper, zinc superoxide dismutase (SOD1) antibody within the spinal cord of patients with amyotrophic lateral sclerosis (ALS). This unique protein species was generated by biotinylation of spinal cord tissue extracts to detect conformational changes of SOD1 specific to ALS patients. To further characterize this protein, we enriched the protein by column chromatography and determined its protein identity by mass spectrometry. The protein that gave rise to the 32 kDa species upon biotinylation was identified as carbonic anhydrase I (CA I). Biotinylation of CA I from ALS spinal cord resulted in the generation of a novel epitope recognized by the SOD1 antibody. This epitope could also be generated by biotinylation of extracts from cultured cells expressing human CA I. Peptide competition assays identified the amino acid sequence in carbonic anhydrase I responsible for binding the SOD1 antibody. We conclude that chemical modifications used to identify pathogenic protein conformations can lead to the identification of unanticipated proteins that may participate in disease pathogenesis.

Keywords

ALS, SOD1, biotinylation, carbonic anhydrase I, mass spectrometry, proteomics

Medical Subject Headings

Amyotrophic Lateral Sclerosis (enzymology, immunology); Biotinylation; Carbonic Anhydrase I (immunology); Humans; Immunoassay; Proteomics; Spinal Cord (enzymology, immunology); Superoxide Dismutase (immunology); Superoxide Dismutase-1

Publication Date

12-15-2010

Publication Title

International journal of molecular sciences

E-ISSN

1422-0067

Volume

11

Issue

10

First Page

4051

Last Page

62

PubMed ID

21152319

Digital Object Identifier (DOI)

10.3390/ijms11104051

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