Amino acid sequence of normal (microheterogeneous) porcine immunoglobulin lambda chains

Area of Science:

• Immunology
• Protein Chemistry
• Biochemistry

Background:

• Previous studies determined partial amino acid sequences of pig immunoglobulin lambda chains.
• Microheterogeneity in protein sequences presents challenges for complete structural determination.

Purpose of the Study:

• To complete the major amino acid sequence of pig immunoglobulin lambda chains.
• To demonstrate a viable fragmentation strategy for sequencing microheterogeneous proteins.

Main Methods:

• Citraconylated pig lambda chains were digested with trypsin.
• Fragments were purified using gel filtration and ion-exchange chromatography.
• Intermediate-sized fragments enabled overlap information for sequence deduction.

Main Results:

• The complete amino acid sequence of pig immunoglobulin lambda chains was deduced.
• Amino acid compositions and partial sequences of selected fragments were analyzed.
• All 14 tryptic peptides were sequenced through overlap information.

Conclusions:

• A suitable fragmentation strategy can successfully sequence microheterogeneous proteins.
• This study provides the complete major amino acid sequence for pig immunoglobulin lambda chains.