XAFS studies of native transferrins and a reaction intermediate revealing a possible pathway for uptake or release of iron

POSSIHLE

PATHW:lY

FOR

OF IRON M.

R.U!.

Neuayb,

E\ansc,

The transferrins

are a family

which play an essential

oxidation

transferrins, lactoferrin

and -transport

of iron in vertebrate<.

protein\ Each lobe

extremly

tightly

but reversibly

in the hish

study

of the

hindin g sites

of the three

XAFS human

serum

transferrin,

has been undertaken,

spin

Ft.j+

chicken

using constrained

oc.otr;rn,ferrin refinement

principai

~cf

human

approach

for data

xerum tran\frrrin.

where

(2).

Recently,

a stable low spin cyanide

CN- has replaced have undertaken

a detailed

in the C-lobe.

of a general

particularly

XAFS

1. P. Aisen

of human

Fe ligands.

has been rq>ortt~d /.‘I. Wz

study of this intermediate

We have used XAFS to provide represents pathway

a new binding for uptake

the role of tyrosines.

49,

adduct

three of the normal

that this intemlediate terms

iron-binding

state [ 11.

A comparative

formed

of bilobal

role in the metabolism

one iron atom

analysis

i,indl

a, S.S. Hamain’

Strange

binds

I’.F’.

ivhic% was only

the firer ciirei,t evitiencc

site for iron. It\ Ggnrficance.

and release

of iron

in transfc‘rrinh.

is discussed.

and I. Listowski.

Antz1I.Rc\,.Riol.h~~y~l. I9XO.

357-393

2. S.S. Hasnain and R.W. Strange, in Bioph_ssicx LICKS Synchrwton Ruciicrtiorl (S.S. Hasnain ed., Ellis Harwood Ltd.), 19x9, 103-121 3. S.K. Swope, N.D. Chasteen, K.E. Weber, J.Am.Chcm.Sw . 1988, I IO, 3835-3830

D-C‘. Harris.

in