Interestingly, H11Y(B) elicited a pH-dependent activity, although this variant lost the pH-sensitive imidazole side chain (pKa = 6.5).
In contrast to previous studies on other hydratases,[ 12] only the G71A variant lost the ability to bind FAD.
Interestingly, the loss of abdominal fat in obese humans that occurred in response to capsinoid treatment in the study by Snitker et al. [ 14] was associated with the Val585Ile TRpolymorphismhism: the subjects with the Val/Val and Val/Ile variants lost about twice as much abdominal fat as the study average, whereas Ile/Ile subjects lost none.
Variants of MCF-7 cells selected for loss of oestrogen receptor lose both IGF-IR and IRS-1 expression, the T47D variants lose only the adaptor proteins (Oesterreich et al, 2001), Thus, they represent an ideal system to study the specific function of IGF-IR with and without expression of the specific adaptor proteins.
The ability to oxidize Mn2+ completely disappeared after the simple E36A, E40A, or D179A mutations in MnP4, and also after the double E35A/E39A mutation in VP1 (the simple E35A, E39A, and D175A variantsants lost over 99.8% of their catalytic efficiency but retained detectable activity on Mn2+).
However, these two YmoB variants lost their capacity to enhance Hha oxidation in vitro (Fig. 3b), in agreement with the suggested role of phenylalanine side chains in channel formation and YmoB-enhanced oxidation of Hha.
Following metal affinity chromatography of TFEα/β, the C92S, C95S and C112S variants rapidly lost the FeS cluster based on the absorbance spectra.
Biochemical analyses showed that these variants also lost the ability to synthesize the essential co-factor thiamine and could no longer utilize carbohydrate sources such as citrate and maltose [ 20, 22, 23].
In HCMV-infected fibroblasts, alternative splicing of the tapasin transcript resulted in an induced level of a tapasin variant lacking exon 3. The tapasin variant had lost the ability to interact directly with MHC I and ERp57, but stabilized TAP expression.
