Conversion of the E1A Cys4 zinc finger to a nonfunctional His2,Cys2 zinc finger by a single point mutation.

Abstract

Trans-activation by the adenovirus E1A 289R protein requires a zinc finger defined by Cys-154, Cys-157, Cys-171, and Cys-174. Whereas individually replacing the four cysteine residues with serines resulted in a loss of transactivation, only three of the Cys----Ser mutants (C157S, C171S, and C174S) lost the ability to bind Zn(II). X-ray absorption fine structure analysis revealed that, in the wild-type protein, Zn(II) is coordinated by four cysteine residues whereas in the C154S mutant, Zn(II) is coordinated by two histidines and two cysteines. The mutant protein probably retains, as ligands, two cysteines on the right side of the zinc finger (Cys-171 and Cys-174) and recruits two of the four histidines on the left side (His-149, His-152, His-158, and His-160), despite the presence of Cys-157. This finding may shed light on the general structural requirements of zinc fingers.

C-Terminal nsP1a Protein of Human Astrovirus Colocalizes with the Endoplasmic Reticulum and Viral RNA

“…Most of the proteins from other viral families that showed sequence similarity to HAstV nsP1a/4 belonged to singlestranded RNA viral families and were related to the formation of the viral replication complex, to the regulation of viral replication, and/or to transcription (8,9,10,26,30,31,42,43,45,46,49,50,51,52,54,55,57,58,61). This observation provides additional support to the idea that nsP1a/4 protein may be involved in RNA replication.…”

Identification of Human Proteins Functionally Conserved with the Yeast Putative Adaptors ADA2 and GCN5

“…To determine possible specificity of hADA2 action in HeLa cells, we compared the effect of hADA2 on GAL4-E1A (38) with its effect on GAL4-VP16. The adenovirus E1A activation domain forms a Zn finger (19,60) and thus apparently is dissimilar in structure from VP16, suggesting possible dissimilarity in function with regard to the human adaptors. As before, hADA2 potentiated GAL4-VP16 activity, while similar amounts of hADA2 had nearly no effect on GAL4-E1A activation (Fig.…”

Intrinsic Structural Disorder in Adenovirus E1A: a Viral Molecular Hub Linking Multiple Diverse Processes

“…4). Furthermore, these interactions require specific zinc coordination, as a single point mutant that converts the zinc finger to a C 2 H 2 type results in a complete loss of transcription activation (140).…”