Crystal structure of streptavidin mutant with low immunogenicity

Abstract

We previously created a low-immunogenic core streptavidin mutant No. 314 (LISA-314) by replacing six amino-acid residues for use as a delivery tool for an antibody multistep pre-targeting process (Yumura et al., Protein Sci., 22, 213-221, 2013). Here, we performed high-resolution X-ray structural analyses of LISA-314 and wild-type streptavidin to investigate the effect of substitutions on the protein function and the three-dimensional structure. LISA-314 forms a tetramer in the same manner as wild-type streptavidin. The binding mode of d-biotin in LISA-314 is also completely identical to that in wild-type streptavidin, and conformational changes were observed mostly at the side chains of substituted sites. Any large conformational changes corresponding to the reduction of B factors around the substituted sites were not observed. These results demonstrated the LISA-314 acquired low immunogenicity without losing structural properties of original wild-type streptavidin.

Cupid and Psyche system for the diagnosis and treatment of advanced cancer

“…Amino-acid sequences in the binding pocket of LISA314 in order to increase its affinity to an artificial analogue, iminobiotin using SBDD. 13,16,17)…”

“…11) Using structure-based drug design and human proteome knowledge, a low immunogenic streptavidin has been designed and proved to be less antigenic in primates after repeated injection. 12,13) The other problem is that human plasma contains a significant amount of biotin as an essential vitamin. Biotin is an important component of enzymes involved in metabolizing fats and carbohydrates, and is present in human plasma, which may cause background problems in the clinical use of streptavidin.…”

“…A series of mutant low immunogenic streptavidin forms that do not interact with wild-type biotin but do so strongly with bis-iminobiotins, named Cupids, were selected. 13,16,17) A series of modified bis-iminobiotins with high affinity to Cupid, named Psyches, have been designed and synthesized. Cupids have been fused with scFv, which form tetramers and stay relatively stable in vivo .…”

Reduced background autofluorescence for cell imaging using nanodiamonds and lanthanide chelates

“…The 100 nm FNDs, on the other hand, increased in size by 11.3 nm upon PEGylation, suggestive of a slightly collapsed conformation of the PEG spacer arm after conjugation. SA is approximately 5 nm across its largest dimension (PDB 3WYP 25 ), thus a size increase of ~10 nm would be expected after its conjugation if SA adopted an ‘exposed’ configuration as depicted in Fig. 1ai .…”

The Crystal Structure of Monovalent Streptavidin

“…For example, to reduce the immunogenicity of SA in clinical use, a low immunogenic SA mutant has been designed and structurally investigated56. Similarly, despite the high affinity of biotin-streptavidin, biotin dissociation results from low endosomal pH7 or being attached to nanoparticles8.…”