Streptavidin

Due to its RYD segment, streptavidin generates number of false positive results where Neutralite avidin doesn’t. This absence of RYD segment in Neutralite avidin improves drastically the quality of the IVD’s.

Streptavidin is a 60 kDa protein purified from the bacterium Streptomyces avidinii. Streptavidin homo-tetramers have an extraordinarily high affinity for biotin (also known as vitamin B7). With a dissociation constant (Kd) on the order of ≈10−14 mol/L,[1] the binding of biotin to streptavidin is one of the strongest non-covalent interactions known in nature (wikipedia.org).

Homologous residues/domains in both proteins are shown in bold type. Positively charged residues (Lys, Arg) are underlined. The RYD-containing sequence in streptavidin, which is homologous to that of fibronectin, appears in bold red. The N- and C-terminal sequences clipped by post-secretory processing (via proteolytic cleavage) on streptavidin are shown in purple. The position of the sugar residue, linked to Asn-17 of avidin in the typical NXT(S) type carbohydrate-containing consensus sequence, is identified by a star (*). Tyr-33 & -43, the nitrated amino acid residue in Nitro-Avidin & -Streptavidin, respectively, is similarly (*) identified. Cys-4 & 83 formed a disulfide bridge in native avidin; natural variant (Ile-34→Thr-34) in ~50% of the molecules.

Streptavidin vs Neutralite

The benefit of the absence of the RYD segment with Neutralite avidin is an increase of the IVD’s quality by a drastic reduction of false positive results. read more

Other Links

The Avidin-Biotin System (ABS)

Application introduction

Neutralite Avidin is a chemically & enzymatically modified avidin characterized by a neutral isoelectric point and the absence of surface glycans. read more

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Streptavidin vs Avidin Amino Acids

.......................................

Asp-Pro-Ser-Lys-Asp-Ser-Lys-Ala-Gln-Val

                     5                      10

                          5                      10                      15         *            20

....Ala-Arg-Lys-Cys-Ser-Leu-Thr-Gly-Lys-Trp-Thr-Asn-Asp-Leu-Gly-Ser-Asn-Met-Thr-Ile-Gly-Ala-Val-

Ser-Ala-Ala-Glu-Ala-Gly-Ile-Thr-Gly-Thr-Trp-Tyr-Asn-Gln-Leu-Gly-Ser-Thr-Phe-Ile-Val-............

                     15                      20                      25                      30

           25                      30             *         35                      40

....Asn-Ser-Arg-Gly-Glu-Phe-Thr-Gly-Thr-Tyr-Ile-Thr-Ala-Val-Thr-Ala-Thr-Ser-Asn-Glu-........

Thr-Ala-Gly-Ala-Asp-Gly-Ala-Leu-Thr-Gly-Thr-Tyr-Glu-Ser-Ala-Val-Gly-Asn-Ala-Glu-Ser-Arg-Tyr-

                35                      40             *         45                      50

      45                      50                      55                      60

Ile-Lys-Glu-Ser-Pro-Leu-His-Gly-Thr-Glu-Asn-Thr-Ile-Asp-Lys-Arg-Thr-Gln-Pro-

Val-Leu-Thr-Gly-Arg-Tyr-Asp-Ser-Ala-Pro-Ala-Thr-Asp-Gly-....................

 55                      60                      65

                     65                      70

........Thr-Phe-Gly-Phe-Thr-Val-Asn-Trp-Lys-Phe-................

Ser-Gly-Thr-Ala-Leu-Gly-Trp-Thr-Val-Ala-Trp-Lys-Asn-Asn-Tyr-Arg-

      70                      75                      80

                75                      80                      85

....Ser-Glu-Ser-Thr-Thr-Val-Phe-Thr-Gly-Gln-Cys-Phe-Ile-Asp-

Asn-Ala-His-Ser-Ala-Thr-Thr-Trp-Ser-Gly-Gln-Tyr-Val-Gly-....

 85                      90                      95

                 90                      95                      100                      105

Arg-Asn-Gly-Lys-Glu-Val-Leu-Lys-Thr-Met-Trp-Leu-Leu-Arg-Ser-Ser-Val-Asn-Asp-....

....Gly-Ala-Glu-Ala-Arg-Ile-Asn-Thr-Gln-Trp-Leu-Leu-Thr-Ser-Gly-Thr-Thr-Glu-Ala-

          100                      105                      110                      115

                    110                      115                      120                      125

Ile-Gly-Asp-Asp-Trp-Lys-Ala-Thr-Arg-Val-Gly-Ile-Asn-Ile-Phe-Thr-Arg-Leu-Arg-Thr-Gln-Lys-Glu

........Asn-Ala-Trp-Lys-Ser-Thr-Leu-Val-Gly-His-Asp-Thr-Phe-Thr-Lys-Val-Lys-Pro-...........

                    120                      125                      130                      135

...............................................................................................

Ser-Ala-Ala-Ser-Ile-Asp-Ala-Ala-Lys-Lys-Ala-Gly-Val-Asn-Asn-Gly-Asn-Pro-Leu-Asp-Ala-Val-Gln-Gln

                    140                      145                      150                      155