gypsum often forms (site 3) in association with sedimentary rocks.
gypsum often forms (site 3) in association with sedimentary rocks.
where does gypsum often form (site 3)?
in association with sedimentary rocks
gypsum is a common mineral, with thick and extensive evaporite beds in association with sedimentary rocks. deposits are known to occur in strata from as far back as the archaean eon. gypsum is deposited from lake and sea water, as well as in hot springs, from volcanic vapors, and sulfate solutions in veins. hydrothermal anhydrite in veins is commonly hydrated to gypsum by groundwater in near-surface exposures. it is often associated with the minerals halite and sulfur. gypsum is the most common sulfate mineral. pure gypsum is white, but other substances found as impurities may give a wide range of colors to local deposits.
gypsum
catterall "et al." hypothesized that some polypeptide neurotoxins that modify voltage-gated channels function via a "voltage-sensor trapping" mechanism. the hypothesis states that neurotoxins similar to poneratoxin, such as alpha-scorpion toxins, act upon sodium channels via binding to the channels' receptor site 3, which normally affects the channels' ability to inactivate. therefore, receptor site 3 neurotoxins often affect sodium channels by slowing or blocking inactivation. normally, the region of the channel where neurotoxin receptor site 3 is undergoes a conformational change of an outward movement to lead to inactivation. receptor site 3 neurotoxins are proposed to prevent this conformational change via interaction with acidic and hydrophobic amino acid residues at that site.
poneratoxin