Crystallographic studies on concanavalin B

Crystallographic studies on concanavalin B

Vol. 57, No. 2, 1974 BIOCHEMICAL CRYSTALLOGRAPHIC Alexander McPherson, AND BIOPHYSICAL RESEARCH COMMUNICATIONS STUDIES ON CONCANAVALIN B Joshu...

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Vol. 57, No. 2, 1974

BIOCHEMICAL

CRYSTALLOGRAPHIC

Alexander

McPherson,

AND BIOPHYSICAL RESEARCH COMMUNICATIONS

STUDIES ON CONCANAVALIN

B

Joshua Geller and Alexander

Rich

Department of Biology Massachusetts Institute of Technology Cambridge, Massachusetts 02 139 Received

February

6.1974

ABSTRACT Concanavalin B has been grown as hexagonal needles and analyzed by x-ray

diffraction

and electron microscopy.

group P61 with -a = 8li

that the crystals interstitial

There is

and 2 = IOli.

weight as the asymmetric

The crystals

unit of the crystal.

maintain considerable

one

are of space

molecule of 30,000 molecular

Electron

micrographs

order after dehydration

demonstrate

and exhibit large

solvent regions. INTRODUCTION Concanavalin

Ensiformis)

B is one of four proteins from the Jack Bean (Canavalis

which were crystallized

by J. B. Sumner between 1918 and 1935 (1,2, 3).

The other three are urease, the only one of the four to be assigned a distinct enzymatic

function,

canavalin,

composition and arrangement diffraction

and concanavalin

A.

The hexameric

of canavalin have recently

analysis (4), and the entire three-dimensional

has been determined physiological

(5, 6). This latter

properties

due to its ability

subunit

been established by x-ray structure

of concanavalin

protein exhibits a number of interesting to bind to cell surfaces (7, 8).

The

function of concanavalin

B in the seed, like that of concanavalin A, is unknown,

and very little

research

has been conducted on its biochemical

The molecular

weight was estimated by Sumner in 1938 to be 45,000 by ultra-

centrifugal

analysis (9). 494

Copyright 0 1974 by Academic Press, Inc. All rights of reproduction in any form reserved.

properties

to date.

A

Vol. 57, No. 2,1974

BIOCHEMICAL

We have crystallized procedure

AND BIOPHYSICAL

concanavalin B by a modification

(1) and studied it by x-ray

and SDS-polyacrylamide

RESEARCH COMMUNICATIONS

diffraction

analysis,

of Sumner’s

electron microscopy

gel electrophoresis. METHODS

Crystallization

- One hundred grams of Jack Bean meal purchased

from Sigma Co. was extracted insoluble residue. the precipitate

with 30% acetone and centrifuged

to remove

The supernatant was brought to 50% acetone concentration,

collected and dissolved in minimal Tris-HCl

buffer pH 8. 0.

The protein solution was dialyzed

for 48 hours vs. distilled

a heavy yield of micro-crystalline

needles collected by centrifugation.

crystals

concanavalin

filtered

4-pentanediol

whereupon large hexagonal needles of

B were formed.

X-Ray

diffraction

The

were dissolved in aqueous ammonia and dialyzed for several days

against 15% Z-methyl-Z,

crystals

water at 4°C and

Analysis

and Electron

Microscopy

were sealed in quartz capillaries photographs recorded CuKo, radiation

at 40 kV and 40 mA.

- For x-ray

by the conventional

examination, means, and

on a Supper precession camera using nickel

generated by an Elliot rotating For examination

anode source operated

with the electron microscope,

microcrysta

.ls

suspended in a drop of water were placed on a carbon covered grid followed by a drop of 2% uranyl

acetate.

Micrographs

at 80kV and a magnification

of 60, 000.

Acrylamide was performed system. parallel

Gel Electrophoresis

according to Laemmli

were taken on a JOEL 100-B operating

- SDS polyacrylamide

(10) using a discontinuous tris-glycine

Eight proteins of known molecular gels and the molecular

gel electrophoresis buffer

weight were run as standards on

weight of concanavalin B calculated according to

Weber and Osborn (11). 495

Vol. 57, No. 2, 1974

Figure

BIOCHEMICAL

1 - An 8” precession

hO1 zone of the reciprocal

of concanavalin

the dark areas to stain.

photograph of (a) the hk0 zone and (b) the

lattice

Figure 2 - An electron micrograph microcrystal

AND BIOPHYSICAL RESEARCH COMMUNICATIONS

B.

of hexagonal concanavalin

B crystals.

of a small section of a negatively

stained

The light areas correspond to protein and

The magnification

is x 750,000.

RESULTS

Electrophoresis

of concanavalin

B on SDS-polyacrylamide

gels

and comparison with known standards showed the protein to have a minimum molecular

weight of 30, OOOf500, which is about 30% lower than Sumner’s

1938 result. 496

BIOCHEMICAL

Vol. 57, No. 2, 1974

When concanavalin parallel

B crystals

enantiomorph

photographs like that shown in

The Laue symmetry

for which $ = 6n are present.

is 6, and only those

The space group is P61 ( or its

~63) and the unit cell dimensions are a = 81;; and c = 1Oli.

Assumption asymmetric

beam

When rotated by 90” about the spindle axis, the

pattern in figure lb was observed. 001 reflections

RESEARCH COMMUNICATIONS

were alligned with the x-ray

with the long axis of the crystal,

figure la were recorded.

of v ,=3.

AND BIOPHYSICAL

of one molecule of 30,000 molecular

unit of the crystal

weight as the

implies a unit cell volume to protein mass

18. This value is within the range of crystalline

proteins compiled

by Matthews (12) although it is rather high, and indicates a large solvent volume in the crystals.

According

solvent volume for concanavalin To verify

to the formula derived by Matthews

B crystals

would be 61%.

that this was the case, microcrystals

were examined in the electron microscope a small portion of the microcrystal.

crystal

of concanavalin

by negative staining.

Figure 2 is

between molecules,

evident from the extensive distribution

The long dimension of the crystal

is the crystallographic

of the electron beam is approximately

along the 110 direction,

onto the 100 plane.

join to form striking

longitudinal

lines running the length of the crystal

as cross striations,

The crystallographic

Regions of heavy staining

lines,

period is the

62i. These dimensions represent

of 32% and 23% along 2 and 2 respectively.

497

as well

period along -c is the distance between

cross lines which is 68A0. Along a - the crystallographic

distance between longitudinal

state.

-c axis,

and the protein is seen projected

alternate

It is

of stained areas in the

that there must be a large solvent regions in the fully hydrated

the direction

B

The light areas correspond to protein

and dark areas to the stain which fills intersticies immediately

the

shrinkages

The volume of the dehydrated

unit

BIOCHEMICAL

Vol. 57, No. 2, 1974

AND BIOPHYSICAL RESEARCH COMMUNICATIONS

This represents

cell is 2, 26 x 105i3.

of solvent of 61%, exactly

a shrinkage in unit cell volume after loss

that predicted

that the precise equivalence

by the formula

of the two values is partly

of Matthews. coincidental,

We suspect since some

small volume in the dry state must be occupied by stain, but the agreement is sufficient

evidence that the asymmetric X-ray

diffraction

intensities

extended to less than 3. Oi resolution, crystals

unit is one molecule. were observed in still photographs that and no appreciable

with exposure time was evident for 60 hours.

concanavalin

B, therefore,

degradation of the

The crystals

of

seem suitable for a three dimensional structure

analysis.

ACKNOWLEDGEMENT Wethank Mrs.

Elaine Lenk for her technical assistance and Dr. Jon King

for the use of his facilities. National Institutes

This research

was supported by grants from the

of Health and the National Science Foundation.

BIBLIOGRAPHY

1.

Sumner,

J. B.

J. Biol.

Chem. (1919) -37, 137 - 142.

2.

Sumner,

J. B.

J. Biol.

Chem. (1926) -69, 435 - 440.

3.

Sumner,

J. B. and S. F. Howell.

4.

McPherson,

5.

Edelman, G. M., B. A. Cunningham, G. N. Reeke, J. W. Becker, M. J. Waxdal and J. L. Wang. Proc. Nat. Acad. Sci. U. S. (1972) -6% 2580-2584.

6.

Hardman, K. D., M. K. Wood, M. Schiffer, A. B. Edmundson, and C. F. Ainsworth. Cold Spring Harbor Symposium on Quantitative Biology XXXVI ( 1971). 271-276.

7.

Goldstein, 1, J. , C. E. Hollerman (1965) 4, 876883.

A. and A. Rich.

J. Biol.

J. Biochem.

498

Chem (1936) 113, 607 - 610. (1973) f 74 155- 160.

and E. E. Smith.

Biochemistry

Vol. 57, No. 2, 1974

BIOCHEMICAL

AND BIOPHYSICAL RESEARCH COMMUNICATIONS

8.

Inbar,

M. and L. Sachs, Nature 223, 710 - 712 (1970).

9.

Sumner, J. B., N. Gralen and I. Eriksson-Quensal. (1938) 125, 45 - 48.

10.

Laemmli,

11.

Weber,

12.

Matthews,

J. Biol.

Chem.

V. K. Nature (1970) 227, 680 - 682. K. and M. Osborn. B. W.

J. Mol.

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Chem. (1969) 244, 4406 - 4412.

(1968) -33, 1491 - 1497.