Engineering of chicken avidin: a progressive series of reduced charge mutants

• Published in: FEBS letters Vol. 441; no. 2; pp. 313 - 317
• Main Authors: Marttila, Ari T, Airenne, Kari J, Laitinen, Olli H, Kulik, Tikva, Bayer, Edward A, Wilchek, Meir, Kulomaa, Markku S
• Format: Journal Article
• Language: English
• Published: England Elsevier B.V 18.12.1998
• Subjects: Animals; Avidin; Avidin - chemistry; Avidin - genetics; Avidin - metabolism; Avidin-biotin technology; Biotin - metabolism; Charge mutant; Chickens; DNA, Complementary; DNA-Binding Proteins - chemistry; DNA-Binding Proteins - genetics; DNA-Binding Proteins - metabolism; Hot Temperature; Mutagenesis, Site-Directed; Protein Engineering; Spodoptera; Charge mutant; Protein engineering; Avidin-biotin technology; Avidin
• ISSN: 0014-5793; 1873-3468
• DOI: 10.1016/S0014-5793(98)01570-1

Avidin, a positively charged egg-white glycoprotein, is a widely used tool in biotechnological applications because of its ability to bind biotin strongly. The high p I of avidin (∼10.5), however, is a hindrance in certain applications due to non-specific (charge-related) binding. Here we report a construction of a series of avidin charge mutants with p Is ranging from 9.4 to 4.7. Rational design of the avidin mutants was based on known crystallographic data together with comparative sequence alignment of avidin, streptavidin and a set of avidin-related genes which occur in the chicken genome. All charge mutants retained the ability to bind biotin tightly according to optical biosensor interaction analysis. In most cases, their thermal stability characteristics were indistinguishable from those of the wild-type avidin. Our results demonstrate that the charge properties of avidin can be modified without disturbing the crucial biotin-binding activity.