TY - JOUR
T1 - Variation of the permeability of bacteriophage T4
T2 - Analysis by use of a protein‐specific probe for the T4 interior
AU - Griess, Gary A.
AU - Khan, Saeed A.
AU - Serwer, Philip
PY - 1991/1
Y1 - 1991/1
N2 - The permeability of bacteriophage T4 and the change in T4 permeability caused by mutation to osmotic shock resistance are investigated here by quantification of the kinetics with which both a DNA‐specific probe (ethidium) and a protein‐specific probe [1,1′‐bi(4‐anilino) naphthalene‐5,5′‐di‐sulfonic acid, or bis‐ANS] bind to T4. In the case of an osmotic shock‐resistant mutant, T40s41, both ethidium and bis‐ANS bind with first order kinetics. The first‐order rate constant (k*) for both bis‐ANS and ethidium is a function of anion type and concentration. Adenosine triphosphate, phosphate, bisulfite, sulfate, and acetate anions all reduce k* below the k* observed when chloride is the only anion. When chloride is the only anion at 25°C, k* values for binding to T40s41 are orders of magnitude above k* values for binding to wild‐type T4 (T4wt). At 25°C, k* forT4wt is too small to measure, but k* for T4wt increases at 50–55°C to values approaching those measured for T40s41, without inactivating T4wt, when chloride is the only anion; during heating, T4wt is stabilized by both ethidium and bis‐ANS. Binding to T4wt is reversible at 50‐55°C, but not at 25°C. Equilibrium binding of bis‐ANS to T40s41 reveals 112 ± 24 sites per T4 capsid. Equilibrium binding of ethidium to T40s41 reveals both high‐ and low‐affinity sites previously observed in the packaged DNA of other bacteriophages. The ATP‐induced decrease in k* is not accompanied by a decrease in equilibrium binding. The following hypotheses are presented to explain the above data: (a) All detected bis‐ANS binding sites on T4 are interior to the outer surface of T4. (b) The value of k* for both bis‐ANS and ethidium is controlled at the port(s) of passage through the outer shell of the T4 capsid. (c) The anions present control k* values at the port(s) of entry, probably by controlling the size of this port. The effects on k* of phosphate explain the otherwise paradoxical observation [P. J. McCall and V. A. Bloomfield (1976) Biopolymers 15, 2323–2336] that in a phosphate buffer the permeabilities of T4wt and T40s41 are the same.
AB - The permeability of bacteriophage T4 and the change in T4 permeability caused by mutation to osmotic shock resistance are investigated here by quantification of the kinetics with which both a DNA‐specific probe (ethidium) and a protein‐specific probe [1,1′‐bi(4‐anilino) naphthalene‐5,5′‐di‐sulfonic acid, or bis‐ANS] bind to T4. In the case of an osmotic shock‐resistant mutant, T40s41, both ethidium and bis‐ANS bind with first order kinetics. The first‐order rate constant (k*) for both bis‐ANS and ethidium is a function of anion type and concentration. Adenosine triphosphate, phosphate, bisulfite, sulfate, and acetate anions all reduce k* below the k* observed when chloride is the only anion. When chloride is the only anion at 25°C, k* values for binding to T40s41 are orders of magnitude above k* values for binding to wild‐type T4 (T4wt). At 25°C, k* forT4wt is too small to measure, but k* for T4wt increases at 50–55°C to values approaching those measured for T40s41, without inactivating T4wt, when chloride is the only anion; during heating, T4wt is stabilized by both ethidium and bis‐ANS. Binding to T4wt is reversible at 50‐55°C, but not at 25°C. Equilibrium binding of bis‐ANS to T40s41 reveals 112 ± 24 sites per T4 capsid. Equilibrium binding of ethidium to T40s41 reveals both high‐ and low‐affinity sites previously observed in the packaged DNA of other bacteriophages. The ATP‐induced decrease in k* is not accompanied by a decrease in equilibrium binding. The following hypotheses are presented to explain the above data: (a) All detected bis‐ANS binding sites on T4 are interior to the outer surface of T4. (b) The value of k* for both bis‐ANS and ethidium is controlled at the port(s) of passage through the outer shell of the T4 capsid. (c) The anions present control k* values at the port(s) of entry, probably by controlling the size of this port. The effects on k* of phosphate explain the otherwise paradoxical observation [P. J. McCall and V. A. Bloomfield (1976) Biopolymers 15, 2323–2336] that in a phosphate buffer the permeabilities of T4wt and T40s41 are the same.
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U2 - 10.1002/bip.360310103
DO - 10.1002/bip.360310103
M3 - Article
C2 - 2025682
AN - SCOPUS:0025981980
SN - 0006-3525
VL - 31
SP - 11
EP - 21
JO - Biopolymers
JF - Biopolymers
IS - 1
ER -